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A Western Rooter plumbing knowledge database.



A Valve

A valve used to manually shut gas off.


(American Institute of Architects) This is basically a self policing regulating body that promotes excellence in architecture. They are heavily involved in all facets of education for their members from internship, to mentoring to licensing and support. A.I.A. is also the preferred method by which sub contractors invoice their customers. Chances are if you’ve been a subcontractor for awhile you know exactly what G701, G702 and a G703 form is for. If you are familiar with all of the AIA forms are you probably have a head ache, they can be tedious but they are ultimately there to protect the Owner.


Generally, in the plumbing industry (it is used a lot in the auto industry because it is so durable) this is black colored plastic pipe and fittings used in drainage, sewer, waste and vents. ABS (Acrylonitrile Butadiene Styrene) pipe/fittings and also PVC (see below) plastics have replaced much of the cast iron, lead and steel pipes formerly used for DWV. Important note is that no solvent cement (and primer) can totally “glue” (solvent weld) ABS to PVC plastic. Under normal conditions, quality ABS (when virgin resins are used) will not crack, chip or peel.


A material that is used to hold gases, liquids or solids or suspended solids on it’s surface or inside pores. The most common absorbent used in the plumbing world is activated carbon.

Absorption Field

This is a seeping field designed to disperse the liquid waste from a septic tank through a filter bed. The septic tank fills with liquid and solid waste and the liquid waste drains off to the absorption field leaving the solid waste behind.

Access Panel

A covered opening in wall made near a plumbing or electrical fixture to allow access for maintenance. In plumbing an access panel would hide control or shut off valves or cleaouts for rodding plumbing fixtures.

Accessible design

An approach to designing buildings, homes and products that renders them easier to access and use by people with physical, sensory, or cognitive disabilities.


Increases the concentration of hydrogen ions when dissolved in water. Acid dissolves common metals.

Acid Dilution Basin

A plumbing appurtenance connected to waste piping servicing a part of a building receiving corrosive or acid waste. Most acid neutralizing basins use limestone as the neutralizing media. Here are some applications where an acid dilution should be used, school labs, hospitals, research facilities, pharmaceutical manufacturing, printing facilities, automotive service centers, film processing, etc.

Acid Waste

Any waste water containing corrosives or acidic liquids that must be neutralized before entering the municipal sewer system. Most often fixtures receiving acid waste are connected to an acid dilution basin which neutralizes acid before the waste water enters the sewer.

Acid Waste Piping

Simply put its waste piping and fittings that are resistant to acid waste. Examples of applications where this is used, laboratories, hospitals, photo labs and printing presses. Some of the materials used in making acid resistant pipe and fittings; glass, polypropylene and polyvinylidene fluoride for really harsh situations. Polyvinylidene fluoride is also fire retardant and when approved can be used in a plenum ceiling.


The measurement of acid concentration in water.


A very strong and hard thermoplastic and in plumbing it is used as a surface material for bathtubs, shower bases, tub or shower surrounds. When used in bathtubs and showers acrylic is usually back with fiberglass to add strength and rigidity. Acrylic is also used to make plexiglass shower doors.


(Americans with Disabilities Act) This term is very important as it relates to plumbing. It affects the height that water closets can be mounted, the types of handles you can install on a lavatory faucet, how much pressure it takes to push down a flush valve handle and those are just a few. Here is a link to the 2010 ADA Standards publication www.ada.gov

ADA-compliant device

A device which is fully compliant, when properly installed, with the current requirements of the Americans with Disabilities Act Accessibility Guidelines (ADAAG), as legislated by the Americans with Disabilities Act of 1990.


A fitting that joins two different types of pipes together. Or/Also a fitting that joins threaded with none threaded pipe (as in: female adaptor or male adaptor, PVC to cast iron pipe).

Adjusting Linkage

An adjustable rod or strap that forms the connection between the lift rod and the ball lever assembly of the drain.


a method to introduce air with water to help in releasing dissolved gasses that contribute to foul odors or unpleasant taste. Aeration can be done in several different ways, air can be bubbled up through the liquid, liquid can be sprayed into the air or the liquid can be agitated oxygenating it by bringing the surface water in to contact with the air. The best example we can give for the use and effects of aeration is the cleansing of the Calumet Sag River in Illinois. Large parks where created along the Calumet Sag River pumping millions of gallons of water through attractively created waterfalls. The results have been staggering.


A device that adds air into flowing water from the end of a faucet to reduce splashing.

Aerator Fittings

a type of fitting installed on a plumbing fixture that mixes water with air. These fittings help with water conservation and reduce splashing.

Aerobic Bacteria

Bacteria living, active and occurring in the presence of oxygen.


Imprinted on many gas valves and appliances. It is the American Gas Association rating.

Air Admittance Valve

A mechanical one way valve used in place of traditional non mechanical (very reliable) vents. It is to allow air to enter waste piping and equalizing pressures. Vents are used to preserve the seal of trap in plumbing fixtures. Also known as auto trap vents.

Air Chamber

A vertical air filled pipe or manufactured spring coil installed above the waterline in a potable water system that absorbs pressure fluctuations when valves are turned off i.e. a shower is turned off or a fill valve in a toilet slams shut. The pressure absorbing devices reduce water hammer. Having air chambers on plumbing fixtures with water connections is code for most municipalities.

Air Gap

The unobstructed physical distance between the outlet end of a plumbing apparatus or piping delivering potable water to a plumbing fixture to the flood rim level of the receptacle (sink, dishwasher, clothes washer or tank) Think of a kitchen sink faucet with a pullout spray if you pulled it out and laid it in the sink you would have no air gap. The air gap protects the potable water system from cross contamination. Please see Backflow Prevention Device, Vacuum breaker, double detector check valves.

Air Inversion

Air inversion pipe lining is used in waste, vent, storm and water main to repair broken piping due to ground settling, pipe deterioration, tree roots etc. It is most commonly used in pipe sizing from 4″ to 48″ in diameter. The piping is prepared by video camera inspection, then

Air Lock

An air bubble in the line that blocks the flow of liquid on the suction side of the pump.


A separation between the waste receptor and the fixture, appliance, or device that is indirectly connected.


The measurement of a water supply’s ability to neutralize acids.

All Thread Rod

a connecting rod used in almost every construction trade. In the mechanical trades it is mostly used to hang piping materials from the underside of a the structure of the building.. Threads are in one direction and standard hex nuts can easily be screwed on to secure a multitude of different hangers. Come in a variety of sizes and finishes. Most common sizes in the piping trades are 1/4″, 3/8″,1/2″, 5/8 & 3/4″ it’s most common finishes are black and galvanized, stainless steel is also a common material.

Ambient Temperature

The average temperature of the air surrounding an appliance.

Americans with Disabilities Act (ADA)

A federal law, passed in 1990, which prohibits discrimination against people with disabilities. The term “disability” means a physical or mental impairment that substantially limits one or more of the major life activities of such individuals. Among the provisions in the law are requirements that impact plumbing products in the design of accessible bathrooms and facilities.


A patented process from American Standard that uses a porcelain surface, an enameling grade steel material and a structural composite backing bonded together to create a sink that is similar to cast iron in durability, heat retention and sound deadening but weighs considerably less therefore it is cheaper to install.


is very similar to the double detector check in that it houses two testable check valves. It has two gate valves one (1) on the inlet and one (1) on the outlet. Here is where things change, an RPZ is used in high hazard situations, where contamination of the water supply would pose a significant health hazard.RPZ (reduced pressure zone backflow preventer) and Double Detector Check Valve

Anaerobic Bacteria

Bacteria that lives and grows in the absence of free oxygen. These bacteria get their oxygen by decomposing substances that contain oxygen.

Angle Stop

An “emergency” stop (valve) that is usually installed before the water supply line (below) to toilets and faucets. Angle stops are to be shut off in case of an emergency or repair and are generally not designed for daily on and off usage. The difference between a “straight stop” and an “angle stops” is that the “angle” stop changes direction by 90 degrees while a straight stop is like most valves and does not change direction.

Angular Discharge Tube

A tube that changes the direction of water flow by 90 degrees.


In plumbing the process by which rigid copper is made soft and pliable. The process consists of heating the metal to a certain temperature and holding that temperature for a set amount of time then allowing the metal to cool slowly to room temperature.

Anode Rod

These sacrificial anode rods are installed at the top of a water heater tank and are generally made of magnesium or aluminum with a steel core. Simply put, through electrolysis the anode rods will corrode before the exposed metal in the tank. If the anode rod has been corroded the water begins to attack the exposed metals in your water heater which will eventually cause it to fail.


(American National Standards Institute) The American National Standards Institute was founded in 1918 and they are the U.S. voice for conformity and regulation. ANSI is compromised of government agencies, academic institutions, manufacturers and contractors and their purpose is to enhance the US global position and to create regulations, norms and guidelines. Those regulations affect almost all businesses from every sector.

Anti Microbial (plumbing definition)

Any plumbing fixture or plumbing accessory that is manufactured with anti-microbial characteristics integral to the product. An anti-microbial plumbing product is one that kills or hinders the growth of bacteria, mold, etc. Vitreous china is naturally anti-microbial when glazed because of it’s glazing and non porous surface. Recently toilet seats are a common plumbing accessory manufactured with anti-microbial properties.

Anti-scald Valve

(please see pressure balanced and thermostatic mixing valve)


Prevents water from trickling back into the supply that is feeding into a sprinkler system.

Anti-Siphon Valve (Vacuum Breaker)

The simple definition is an anti-siphon valve is a device installed on a water supply line that prevents water from backing up into the potable water system. Vacuum breakers are an example of an anti-siphon valve. Anti-siphon valve are most commonly spring loaded one way valves. When the direction of flow is going in desired direction all works well, if the direction of liquid changes the valve slams shut prevent back siphonage.

Apron (or Skirt)

The decorative portion of a bathtub that covers the rough-in area of the tub. It is most easily recognized on a whirlpool tub, the apron is most often removable to be able to service the tubs plumbing and or motor.


(American Supply Association) Formally founded in December of 1969 the ASA is an organization that represents wholesale distributor and their supplier in the plumbing, heating, cooling, industrial and mechanical pipe, valve and fittings industries.


(American Society of Mechanical Engineers) A professional member ship group founded in 1890, this group originally came together to test steam vessels because of the numerous failures. Now it is the premiere standards development organization. Setting codes and standards throughout the mechanical trades.


(American Society of Sanitary Engineering) Founded in 1906 by Henry Davis Chief Plumbing Inspector for the District of Columbia. This group consisted of plumbing engineers, plumbing inspectors and installers all with the common idea of making plumbing safer and more universal though out the United States. They also have quite a bit of influence as to the adoption of plumbing code and the vital testing of plumbing product and theory.

ASTM International

(formerly know as American Society for Testing Materials) Formed in 1898 by chemists and engineers from the Pennsylvania Railroad they organized the railroad’s new chemistry department, where they investigated the technical properties of oil, paint, steel, and other materials the Pennsylvania Railroad bought in large quantities. Organized a new set of standard that they expected their suppliers to follow. At the present they are “globally recognized leaders in the development and delivery of international voluntary consensus standards” Please visit their web site for a more detailed history.


A flexible metal rod, usually made of spring material, with a cutting or clearing device on one end. It is used to clear clogs in drains. Closet augers, also called toilet auger, have a tubular guide to permit entry through the toilet trap design. Larger, longer augers are used to clean underground drain lines and may be motor driven.

Automatic compensating valve

A valve that is supplied with hot and cold water, and provides a means of automatically maintaining the water temperature selected for an outlet. Automatic compensating valves are used to reduce the risk of scalding and thermal shock.



Back Flow

The circumstance of water traveling from one system back into any part of the main distribution system, usually by siphoning.

Back Flow Preventer

Prevents water or other substances from traveling back into the main distribution system. A backflow preventer is required for sprinkler systems, handheld showers, pullout faucet sprouts, kitchen sprayers, and other various devices.

Back Flush

To temporarily reverse the normal liquid flow through a plumbing system.

Back Pressure

Pressure against the flow of fluid in a piping system.

Back Siphonage

The reverse flow of liquid due to a partial vacuum in the pipe.

Back-up Sump Pumps

Literally any pumping device that acts to back-up the primary sump in case of power failure or primary pump failure. Most back-up sump devices include some sort of marine battery either wet cell or maintenance free gel battery. There are back-up sump pumps that use no electricity and function on incoming water pressure.


A flowing back or reversal of the normal direction of wastewater from homes and buildings, leading to the possible contamination of potable water systems.

Backflow prevention device

Any mechanical device designed to automatically prevent backflow.

Backpressure in a Plumbing System

Pressure that is less than atmospheric pressure. If a sewer drain line is running at 100% capacity and with greater than intended velocity if the waste water passes another drain outlet it could cause a negative pressure. This negative pressure can pull a water seal from a trap causing sewer gas or vermin into the living space. Extremely high winds can also pull the air from the plumbing vent pulling the trap seals with it.


A clogged plumbing fixture due to drain stoppage.

Backup (Sewer)

The overflow of water usually combined with waste from a plumbing fixture caused by a blockage in the fixture drain or waste line servicing the aforementioned plumbing fixture.

Backwash Cycle

No this isn’t what you’re sibling leaves in the bottom of the Gatorade bottle. The Backwash cycle is a process a water softener or water filter goes into, usually pre-programmed for off hours, whereby the water flow is reversed cleaning the filter media. The waste water is sent to an open site drain.

Backwater Valve

A valve within the sewer line that prevents sewage from reversing travel into the building.


An object or screen placed in a plumbing fixture or appurtenance to change the direction of or retard the flow of water or flue gasses. The most common baffles used in plumbing are the ones found in a grease separator. The baffles are used to slow down the incoming waste water, allowed the suspended grease and solids to cool and rise to the top for easy removal.

Balancing Cocks or Valves

A valve with an adjustable partition or gate which can be used to increase or decrease flow. They also have self sealing ports in which thermometers can be inserted to check the temperatures of the liquids.

Ball Check Valve

a type of backflow preventer that uses a ball to seal against a seat in a valve. It is installed on a water line so that water is allowed to flow in one direction only.

Ball Passage

The ball passage indicates the size of a ball that can pass through a toilet’s trapway. It also refers to the size of the trapway of a toilet; the trap size is to be 1/8″ larger than the ball that can pass through it.


the fill valve that controls the flow of water from the supply line into a gravity-operated toilet tank. It’s controlled by a mechanism that floats in the tank water. When the toilet is flushed, the float drops and opens the ballcock. This releases water into the tank and/or bowl. As the water in the tank is restored, the float rises and shuts off the ballcock when the tank is full.


Products and buildings are considered “barrier-free” if they permit access by all users, including those in wheelchairs. In plumbing products, the term can refer to showers that do not have a lip preventing wheelchair access, as well as sinks and water fountains that are useable at different heights.


Generally circular, vessel with slopping or curving sides for holding water for washing. Usually used to refer to a sink of some sort.

Basin Wrench

A long-handled wrench with jaws mounted on a swivel that can reach nuts in a previously installed sink.

Basket Strainer

A device shaped like a cup or a basket with holes or slots that fits inside a drain that allows water to drain out but catches debris before it enters the waste piping.


Brushed Chrome

Beam Clamps

A clamping device used when beams are the only thing used for support. They are used in conjunction with pipe hangers to ensure proper support and pitch. The beam can be c-clamp type or can span the entire beam.

Bench Mark

It is a known elevation set throughout a building or job site that all trades can use to locate proper elevations for doors, windows, plumbing fixtures etc. An elevation will be set usually by the general contractor in accordance with the engineer and all trades can measure from that elevation. It can also be a mark on a permanent flat service whereby it is used to lay out walls, columns, stairwells, etc.


A generic term given to all elbows made from all types of piping material.


aka bibcock or hose bibb – typically a faucet with nozzle bent downward. Also called: outside/outdoor faucet/spigot or garden faucet.


(pronounced Bid-day) Consisting of a washing basin, hot/cold faucet, and sprayer, it is mounted near a toilet for the purpose of washing one’s self.


Any material subject to degradation to simpler substances by way of biological action i.e. aerobic and anaerobic decomposition. Substances that are considered biodegradable are detergents, human waste, organic matter.


Refers to the finish on the unglazed areas of vitreous china fixtures.

Black Water

Waste water from toilet, urinals, bidets or food prep receptacles or waste water from drains receiving chemical waste.

Bleed (Water System)

To drain a pipe or piping system of excess air by opening plumbing valves or appurtenances exposed to the atmosphere i.e. shower valves, faucets and drain down valve.

Blind Plug

A plug or cap used on no-hub piping to end a drain line. It is affixed to the end of the pipe by a no-hub coupling.


Blowbags are devices that clean drains. They are made up of a rubber bladder with a hose fitting on one end and a nozzle on the other. The blowbag is attached to a water hose and the hose is inserted into a clogged drainpipe. Water is expelled in pulses, forcing water through the clog.


Brushed Nickel


(Building Officials Code Administrators International)

Body Sprays

For all practical purposes these are shower heads. Some are hand held, some are on a sliding bar so that the can be moved up or down and some are positioned throughout a shower to spray on different parts of your body while showering.


A tank that heats water and turns it to steam for power or hot water.

Brackish Water

Any water containing bacteria between 1,000 and 15,000 ppm of dissolved solids.

Braided Supplies

A flexible pressure tubing usually made of synthetic material that is encased in braided threads of steel or stainless steel. The braided covering protects the synthetic tubing from damage due to abrasions and crimping.


any part of a drain system other than the main, riser or stack; also known as a lateral line.

Branch Vent

A vent connecting one or more individual vents with the vent stack.

Branch Water Piping

The local domestic water piping that extends from the vertical risers (or other mains) and supplies water to plumbing fixtures or equipment.


An ancient alloy, composed primarily of copper and zinc, used in the manufacture of faucets and other plumbing fittings. Small amounts of other alloying materials are also added for various types of brass to address the requirements of specific applications. Brass is also the term for a faucet finish, also known as polished brass.

Brass Seats and Seals

In a plumbing valve the surface area on the moving part of a valve and the stationary part of the valve. When the moving part of the valve comes in contact with the non-moving part the flow of water stops completely. The most common material used for valves seats is brass. Brass seats eventually have to be repaired or replaced because with continual use the seating surface degrades over time.


uses (How To) Similar to soldering, brazing is the process of filling a void (for plumbing) in a pipe joint with a filler metal to join pieces of pipe or fittings. Brazing filler metals generally have melting temperatures above 1,100 degrees Fahrenheit. Most brazing filler metals contain some amount of silver, copper and phosphorus.

Break Tank

A type of vessel that holds a supply of water that is to be used for a specific purpose (mainly heating) other than for consuming or flushing plumbing fixtures. It is filled through an air gap (to prevent contamination of the domestic water system) and the water supplying the tank shuts off, when filed to a predetermined height, by an automatic shut off valve.


Abbreviation for “British Thermal Unit”; a measurement of heat equal to the amount of heat necessary to raise one pound of water one degree Fahrenheit at sea level. (One BTU is equal to about 250 calories.)


The word bubbler has a rather interesting back story. It’s definition is simple, it’s another word to describe a drinking fountain like the ones you see at a park. However, there is really only one place in the country where it is used with regularity and it’s in the Badger State of Wisconsin. Check out this article for more on this strange little regional phenomenon.

Buchan Trap

Obsolete way of venting a waste water drain. An in-line trap with a vent on the inlet side. Also known as a Bristol interceptor.

Building Drain

The lowest point of a drainage system where all of the interior drainage piping meets and is discharged into the sewer.


A pipe fitting used to join two pieces of dissimilar sized piping. There are many different joining methods but the most frequently used is threaded on both ends.

Butterfly Valves

The butterfly valve has some similar features to that of the wafer check valve. It is very thin and lightweight so space and support are not issues. It is closed using a wafer or disc that is mounted on a rod that is secured in the middle of the valve. The rod exits the valve at the top and ends with a handle that incrementally controls the internal disc. In the open position the disc is parallel to the pipe in the closed position the disc is perpendicular to the pipe closing off flow. These types of valves can be used to control flow and are especially affective in tight spots. Most times the handles are spring loaded and allow you to lock the valve into a certain position.





CAD (Computer Aided Design)

A method of designing building mechanical systems using a well known computer software. Prior to CAD, engineers and architects had to design and layout all of the different piping trades by hand and with the aid of the subcontractors “shop drawings”. Now most of it’s done via computer. There are still changes in the field but those changes are always relayed to the engineer and are updated on the master CAD files.

Cast Iron

Formerly used for drainage, sewers, waste, and vent pipe and fittings. Very durable and heavy metal. Today, many top quality bath tubs are still made with cast iron. Pipes and fittings today are generally only used for commercial applications where fire ratings are involved.

Cast Iron Pipe and Fittings

Plumbing sewer and vent pipe and fittings that are made from cast iron. It is manufactured in two (2) types–hub and spigot, and no-hub. The hub and spigot pipe and fittings are manufactured as either service weight or extra heavy. This relates to the wall thickness of the pipe and fittings, the extra heavy having a thicker wall thickness. The extra heavy pipe and fittings are rarely used today and availability of various fittings is limited. The hub and spigot type pipe is manufacture in three (3) lengths–five (5) and ten (10) foot single hub, five (5) double hub and thirty (30) inch double hub. Single hub means the pipe has one (1) end that is plain and the other has a hub and double hub means there are hubs on both ends. The no-hub pipe and fittings are manufactured in service weight and the pipe only comes in (10) foot lengths. The hub and spigot pipe and fittings are joined by using either neoprene gaskets or lead and oakum. The no-hub pipe and fittings are joined by using a stainless steel band with neoprene gasket that is manufactured specifically for the no-hub pipe.

Catch Basin

A below ground container with a grate that collects storm water run-off. It catches debris, preventing water pollution.


A style of bathroom lavatory faucet having combined spout and handles. Handles are 4″ from center of handle-to-handle. Also a single handle faucet installed on 4″ center-to-center faucet holes.

Ceramic Discs

similar to brass seating material, ceramic is the hardest material you can use in seating material. One ceramic disc rotates and slides against the other. As the holes or notches in the discs align the water passes through. Ceramic discs are completely unaffected by water temperature so the neither expand nor contract, they are not damaged by debris in the water line.


A cesspool is an underground excavation in the ground that receives the discharges of a drainage system. It retains the organic, solid matter and permits the liquids to seep through.

Chair Carrier

(Please see Fixture Carrier)

Check Valves

A check valve is a one way valve in that is has one inlet and one outlet that allows the a liquid to travel in one direction. It is used to halt the flow of the aforementioned liquid in case of a drop in pressure or reverse in directional flow. The majority of check valves used in the plumbing industry work automatically meaning when the pressure or direction changes the valve slams shut.


In the plumbing industry that generally refers to porcelain or vitreous china used in making toilets and lavatory sinks. China is a material that is made from clay and is glazed and high fired in a kiln. The finish is very hard and smooth. An excellent product for toilets and lavatories. Fire clay is another form of china that is used for large farm sinks.

Circuit Setter

A circuit setter is a balancing type valve used in an HVAC or plumbing system to regulate pressure in the whole system or within part of the system. In a plumbing system it is used to regulated pressure between hot and cold water inside the potable water system. Many years ago a check valve and a ball valve where used, the check valve would shut down a hot or cold water supply if there was a sudden drop in pressure and the ball valve with a memory stop was used to regulate flow. This prevented cold or hot water bleed over if the pressure was increased or decreased in either supply piping.

Circuit Vent

A branch vent that serves two or more fixtures with integral traps like a water closet or fixtures with p-traps installed in a battery (fixtures grouped together). The vent extends from the top of the horizontal waste branch in front of the last fixture waste to the main vent stack of a building drainage system.


An underground rainwater storage container.

City Sewer

sewage disposal system operated by the city or county.


An accessible opening that is placed in a drainage line at a convenient location to accommodate drain cleaning equipment in the event of a line blockage.

Cleanout Cover

An esthetically pleasing cover (usually chrome plated) that hides a cleanout. The cleanout cover is usually furnishing with a chrome center screw that threads into the cleanout plug.

Cleanout Plug

a plug in a trap or drain pipe that provides access to the drain line for the purpose of clearing an obstruction.

Clevis Hangers

A piece of metal bent in the shape of a “U” that is used to support pipe or conduit from a structure. The “U” has holes through both ends through which a rod is inserted and attached to the rod is a yoke with a hole in it through which a threaded rod is inserted and the threaded rod is attached to the structure.

Close-coupled Toilet

A two-piece toilet. The toilet tank is separate from the toilet bowl. This is the most common type of toilet.


Another phrase for toilet.

Closet Auger

A flexible rod with a curved end used to access the toilet’s built-in trap and remove clogs.

Closet Bend

a curved fitting mounted immediately below the toilet that connects the closet flange to the toilet drain.

Closet Flange

An anchoring ring secured to the floor.The base of the toilet is secured to this ring with bolts.


A faucet or valve that regulates the flow of water; it is also known as a ballcock.

Cock Hole Cover

We know it’s a silly word but it is an actual plumbing term. It is simply this, a metal cover that is inserted onto an empty hole in your kitchen sink or counter top. They come in different finishes like chrome, brass, white and stainless steel. Say you replace your old kitchen sink faucet that has a side spray with an updated model that has a pull out spout. The faucet with the side spray used a four hole sink. The one with a pull spout uses three holes or one if you don’t use a cover plate, you’ll have one extra hole. You’ll need the ever famous cock hole cover.

Coffee Station

In a commercial tenant space, a place for employees to get coffee, ice, or have lunch or take a break. Coffee stations typically consist of a kitchen sink, faucet, coffee maker, and refrigerator. Depending on the municipality the coffee station may require a grease interceptor and a floor drain. The coffee maker and the refrigerator will require a backflow preventer.

Cold Chisel

A steel hardened tool that is manufactured in various lengths and diameters with a beveled end that is used for chipping and breaking concrete, cast iron, steel and other hard material.

Combined or Combination Sewer

piping that is designed to carry both rain water with sewage. This method of evacuating waste water is being phased out around the country in favor separating the storm sewer from waste.


Generally also stands for toilet.

Common Vent

A drain system within a building that connects 2+ fixture branches on the same level.

Composite Material

A material used to manufacture counter tops and and sinks. Composite materials usually have an acrylic base that is colored and different aggregate materials are introduced to give the surface a unique look and in some instances adds strength. Quartz composite sinks are a great example of composite material were quartz is added to give it a unique look and adds strength and resists corroding and chipping.

Compression Fitting

A pipe connection where a nut and sleeve is place over a tube, compressing it tightly around the tube as the nut is tightened; this forms a seal without soldering.

Compression Fittings

A kind of tubing or pipe connection where a nut, and then a sleeve or ferrule is placed over a copper or plastic tube and is compressed tightly around the tube as the nut is tightened, forming a positive grip and seal without soldering. Also a flexible connector that has a nut and gasket designed to attach directly to an SAE standard compression thread, without the use of a sleeve or ferrule.

Compression Valve

A valve used for water faucets. It opens and closes by raising and lowering a horizontal disk.

Console Lav

A table-like fixture with an integral lavatory. The back is fixed to a wall and the front is supported by consoles (brackets) or legs.


One of the basic elements (Cu), copper is used for plumbing piping, and is one of the alloys used to make brass, a key material in the manufacture of faucets and fittings.

Copper Pipe and Fittings

Copper pipe and fittings are material used in drainage, waste and vent pipe as well as potable water piping. Copper is fairly easy to work with, has excellent thermal conductive properties and it is very durable. Copper comes in a wide variety of pipe sizes and can handle water, oil and gas.

Copper piping

Water line made of copper or a copper alloy. Copper pipe is usually rigid; tubing is flexible. Copper will not rust and has a long life cycle, but it can corrode, especially at solder joints, which could cause leakage. It is primarily used for potable (drinkable) water.

Core Toilet Rooms

A group of centrally located toilet rooms in a commercial, industrial or institutional building. These toilet rooms are usually designed to accommodate a certain number of workers or guests per floor or per area of a building. If core toilet rooms are in a multi-level building they are usually stacked on top of one another using a common wet column.


A fitting that joins two pieces of pipe (or other fittings) together.


Polished Chrome


Chlorinated PolyVinyl Chloride is a plastic product designed for drinking water at temperatures up to 180 degrees (where code permits). Comes in straight or rolls, generally off white colored (orange for fire sprinklers).

Cross Connection

Any connection in plumbing that allows potable water to be connected to a non potable water source. Cross connections can be a potentially serious health hazard. Here is an example of a cross connection : a good number of utility sink faucets come with a threaded hose connection at the end of the spout. This is used to attach a hose so a floor or room can be washed down. If the spout or faucet is not installed with a vacuum breaker and the hose is dropped into the utility sink filled with water and a cleaning chemical you have a cross connection.


Similar to a pipe, a construction of concrete that allows drainage underneath a road.


Abbreviation for Cold Water


Abbreviation for Cold Working Pressure


Abbreviation for Copper Water Tube (refers to nominal pipe size).


Copper x copper, meaning the fitting is sized for copper pipe.

Cycle Time

Refers to the amount of time it takes a toilet to complete it’s flush cycle, from the instant it is flushed until the water supply shuts off.




Refers to the seal caused by water in a trapway.

Desanco Fitting

A compression adapter that attaches tubular brass fittings to PVC pipes.


To prevent debris build-up within the valve, a diaphragm is a flexible membrane within a valve that regulates water flow from the supply lines.

Dip Tubes

Usually a plastic tube that is inserted into the inlet side of a domestic water heater. The tube forces the incoming water to the bottom of the heater, (closest to the heating elements) whereby the water is more evenly heated throughout the tank.

Direct Tap

A clamp on a branch line that takes it off of the main line.

Discharge drain

A drain that discharges water into a drain system or into the ground through a channel. French drains are one example of a discharge drain.

Discharge Tube

A discharge tube is an outlet tube that connects a disposer/sump pump to a drain line.

Dishwasher Air Gap

An apparatus that is usually mounted next to your faucet, either on the counter or in a knockout on the kitchen sink. This device connects from the waste outlet of the dishwasher to the airgap and from there it connects to a waste opening in the p-trap of the kitchen sink. It allows waste water to flow into the waste piping however of the waste piping should ever back up, the waste water will not back up into the dishwasher because of the aforementioned air gap. Please see our diagram for further clarification.

Dishwasher Tailpiece

An adapter that unites a basket strainer to a drainpipe with a dishwasher inlet.

Disposal Field

A series of trenches that distribute waste uniformly into the soil.


Valves which direct water to various outlets. They are used in showers, tub & shower combinations, bidets, Roman tub fillers and kitchen faucet sprayers.

Double Detector Check Valve

The double detector check assembly is installed with one (1) gate valve on the inlet of the valve and one (1) gate valve on the outlet side of the valve. These assemblies prevent back flow or back pressure in nonhazardous situations and are most used to protect the potable water system of a building from the water in a fire prevention system. A detector check is made with a by-pass assembly and meter to detect any unauthorized or illegal taps, test cocks are also present so that required yearly testing can take place. Each check valve can be isolated and tested independently to see if they are leaking and operating properly.

Double Vent

See Relief Vent

Downspout Piping

Also known as storm water piping. It is the piping system that handles the discharge of rain and melted snow water to the city sewers, retention ponds, or ground level pavement or grassy areas. On the interior of buildings the piping material is usually made of cast iron, copper or PVC. When it is installed on the exterior of the building the piping material is usually sheet metal like the downspouts on a private residence.


The opening to a piping system that is used to remove wastewater from a fixture or system and transport it elsewhere for treatment or reuse. Most drains are open, but floor drains may have a protective grate over them.

Drain Piping Pitch (Slope)

In plumbing the grade at which the drain piping is installed to assure that the waste water flows at a speed that allows the piping to be self scouring. Meaning the turbulence and movement of the water cleans the inside of the pipe. 1/4″ per foot is a common pitch for plumbing. We like to say a lazy sewer is a good sewer, if the water is moving too fast it may move past the suspended solids leaving them behind. If enough waste is left behind you have the potential for a build up and an eventual blockage.

Drain Tile System

A system of pipe usually made of corrugated plastic, PVC or clay tile that collects subsoil drainage and allows it to dump into a sewer or water retention area. Drain tile is usually perforated to allow water to seep into the pipe and it is widely used under basement floors or under concrete footings, this keeps water from getting into basements or washing out backfilled soil. Drain tile is also used in athletic fields, farm fields and in any situations where water needs to be removed quickly.

Drainage Fittings (Cast Iron)

This a true plumbing professional term. Obviously all Drainage, Waste and Vent (DWV) are types of fittings used for drainage however cast iron drainage fittings are threaded fittings that are specifically used for drainage piping. These fittings are a dying breed and are only used in certain areas or in repair situations. These fittings are made with pitch built in to assure proper flow.

Drip Leg

A stub-ended pipe installed at the low point on a gas line; collects condensation and debris and allows for its removal; also known as a sediment trap

Drop in Bath Tub

A bathtub that is built with an integral lip or ledge that is meant to fit into or be dropped-into a pre-framed area that is to receive the bathtub.

Drop-in Anchor

These are anchors that are inserted into a pre-drilled hole in concrete. The anchor has a metal cam inside that when hit or “set” flares the bottom out to secure it in the concrete. Drop-in anchors are threaded on the inside to accept all thread rod or bolts and they are commonly used in conjunction with a clevis hanger to hang piping from the underside of a deck.

Drum Trap

This type of trap is no longer used. It was formerly used as a trap in sewer lines.

Drum Traps

Very rarely used, a drum trap is a circular metal canister with the inlet near the bottom of the trap and the waste outlet is at the top with a removable cover. Ideally the drum trap is installed in a place with easy access so you can remove the cover to clean. Unfortunately many drum traps we’ve encountered are buried behind a wall or the cover is unable to be removed, fused together by time. So when drum trap stop they are extremely difficult to clear by rodding because of their inlet and outlet configuration. Drum traps were installed so people could find jewelry or valuables if lost down the drain. The trap would catch the ring or earring by sinking to the bottom, the likely hood that a valuable would flow into the waste opening at the top of the trap is highly unlikely.


A high-efficiency toilet that gives users the choice of flushing with the maximum amount of water allowed by law (1.6 gpf in the United States) or less water. The average amount of water used by the toilet cannot be more than 20 percent less than the maximum allowable, qualifying it to be considered high-efficiency and eligible for WaterSense labeling.

Duo Valve

A hot and cold valve with a single on/off lever used for washing machines.

Duplex Pumps (Ejector or House Pumps)

This is simply a pumping system that uses two pumps instead of one. These pumps are usually equipped with an alternator that alternates pumping cycles to minimize wear on one particular pump. The alternator can be set to alternate the pumps in a variety of ways i.e. every other cycle, every ten cycles or it can be set by usage parameters if equipped with the right controls.


Abbreviation for Drainage, Waste & Vent systems. Not for drinking water.

Dynamic Pressure

The pressure when the water IS flowing.



E Coli

An abbreviation for Escherichia Coli, a bacteria that reveals fecal contamination.

Earthquake Strap

A metal strap that secures a water heater to a building’s frame or foundation.


Generally expressed as a percentage, a term that describes the ability to utilize energy.


Liquid waste, potentially hazardous, generally refers to liquid waste from septic tanks.

Ejector Pits

A round, square or rectangular pit (collection vessel) that can be made from cast iron, steel, PVC, fiberglass, concrete or clay tile. They are used in applications where the sanitary waste that flows into them is lower that the main sewer and by mean of an ejector pump(s) the waste is pumped up and out to the main sewer. They must always have a gas tight cover and be properly vented.

Ejector Pumps

A device manufactured to elevate water, sewage (suspended solids) or liquid waste from a lower level to a point of discharge where it can be drained away by gravity into a sewer or drain.

Elbow (aka ELL):

A fitting with two openings that changes the direction of the line. Also called an ell. It comes in a variety of angles, from 22 1/2° to 90°, though by far the most common is the 90°.

Elevated Vacuum Breaker

A vacuum breaker that is elevated off the floor at 7ft-6″. There is a very good reason it is elevated at 7ft-6″ it is above the average height of a man with his arms stretched over his head. Huh? Yep, the reason for this is a person cannot take a hose and stretch to place it above the vacuum breaker rendering the vacuum breaker useless. I know how about we just step on a chair? Whatever…that’s the reason for 7ft-6″. Elevated vacuum breakers are slowly dying.


The shape of the front of a toilet bowl. Generally about 2″ longer than the standard “round front” bowl.


An opaque vitreous composition applied by fusion to the surface of metal fixtures such as cast iron and pressed steel tubs, lavatories and sinks. Please do not confuse enameled steel with enameled cast iron. Cast iron with enameling is much more durable.

Energy Policy Act of 1992

Among the provisions of this federal legislation, the Energy Policy Act of 1992 (EPAct ’92) required that all residential toilets had to flush using no more than 1.6 gallons per flush.

Energy Star

An international standard for energy efficiency that originated in the United States. Electrical appliance must conform to certain standards in order to qualify. Dishwashers and washing machines are two of the appliances that can be Energy Star Rated.

Epoxy Pipe Lining

Epoxy lining of plumbing pipes is used when the cost of digging and or tearing walls and ceilings apart proves to be too cost prohibitive. There are several different types of epoxy pipe lining and they are used based on application type.

Epoxy Pipe Restoration

This method is used mostly in water piping and it is most effective in pipe sizes from 1/2″ through 4″. Although some companies have different techniques most have these steps that are common for all. Drain down of water piping being restored, heated and compressed are introduced to the piping to dry pipe thoroughly. A sand slurry mixture is blown into the pipe to scour the inside of the pipe walls, knocking off any scale or oxidation. Finally the epoxy coating is blown in coating the inside of the pipe. Check out the video of CuraFlo explaining the process.


(pronounced ih-skuhch-uhn) An ornamental or protective flange or shield beneath a faucet handle, This part covers the faucet stem and the hole in the fixture or wall. They are also found around shower arms, stop valves, and other piping that comes through the wall. Typically cosmetic, some escutcheons are gasketed to help with waterproofing, like escutcheons for body sprays.

Expansion Tank

A tank usually installed on a closed hot water line used to absorb excess pressure due to thermal expansion. Because water expands when heated, the water needs a place to expand to hence the expansion tank.

Express Riser

A domestic water riser is used to distribute potable water to floor levels that require potable water to function in both commercial or residential applications. For a high rise building maintaining water pressure suitable to proper fixture function is critical. An express riser is a water riser thats sole purpose is to bypass lower floors and service upper floors so adequate water pressure is maintained.

Extension Tailpiece

A length of tubular brass or PVC piping used to extend the waste on a kitchen, lavatory or service sink. Connections or usually Slip Joint or threaded.

Extra Heavy Soil Pipe

Cast iron soil has been used for drainage, waste and vent piping for hundreds of years. Extra heavy soil pipe is specified for extreme conditions and has a very high crush strength. It’s popularity has declined sharply over the last 30 years. It was not uncommon to see extra heavy soil pipe used in schools, hospitals and prisons.




also known as flow; the proper slope or pitch of a pipe for adequate drainage


A sink fixture that controls water flow. Most sink faucets have a mixing valve that allows the user to modify the temperature of the water by changing the ratio of hot to cold. Faucets may come with either two handles, one for hot and one for cold, or with a single lever handle that changes the mix ratio.

Faucet screen

A small metal screen used to catch small debris in the water system, found in the faucet arm nozzle. Water hoses for washing machines may also have a screen to prevent debris from damaging the water valves.

Faucet Types

A faucet is any device that controls the flow of water. The most common types of faucets used in plumbing are kitchen, lavatory, bar, service sink, hose bibbs, shower valve, tub filler and yard hydrants.

Federal Plumbing Code

(Please see National Plumbing Code, BOCA, & IAPMO Uniform Plumbing Code)

Female Fitting

A fitting in which another fitting or pipe is inserted.


A manufacturer. Commonly means rubber coupling


Abbreviation for female hose threads.


Glass in a fibrous form used in making products such as boats and bathtubs.

Fill Valve

Most commonly referred to as a Ball Cock, the fill valve controls water to the tank of a tank type toilet. The fill valves is operated by means of a float. Most fill valves also have an anti siphon device or vacuum breaker to ensure there is no cross contamination from the water in the tank to the potable water supply.

Finish Plumbing

Plumbing fixture installation to make a system usable.


Abbreviation for female iron pipe size threaded fitting. Threads are inside the fitting.


A device designed to control and guide the flow of water. Examples include faucets, shower heads, shutoff valves, shower valves, and drinking fountain spouts. Some people call these “fixtures,” but that term means something different to the plumbing industry. The differing usage of “fitting vs. fixtures” can lead to unintended consequences, such as when legislation calls for changes in fixtures, although the true intent involves changes in fittings. (See “Fixtures.”)


A device for receiving water and/or waste matter that directs these substances into a sanitary drainage system. Examples include toilets, sinks, bathtubs, shower receptors, and water closet bowls. The term is used erroneously in common vernacular to describe fittings. (See “Fittings.”)

Fixture Carriers

A device that is installed behind a finished wall and anchored to the floor to mount and off the floor plumbing fixtures i.e., lavatories, wall hung toilets, urinals and slop sinks. It is most commonly used in commercial and institutional applications due to increases wear and tear.

Fixture Units (Drainage)

The quantity of load producing effects a plumbing fixture has on a plumbing drainage system. The number is based on the probable discharge of waste water into the plumbing drainage system by different fixtures for a single operation and on the average time between operations. The rate of discharge through a plumbing fixture of 7.5 GPM is termed one fixture unit.

Fixture Units (Supply)

The measure of how much water a plumbing fixture needs for proper function. The plumbing valve used by a particular fixture and its function is based on the volume of water it uses on a single occasion and on the average time between operations.


The hinged, movable part of a type of shut off valve that prevents or shuts off flow. A common type of flapper is found at the bottom of a toilet water tank. It is raised to start the flush cycle and closes when the tank is empty, allowing it to refill.

Flapper Valve

A piece of equipment on the bottom of the toilet tank that opens and closes, regulating the flow of water from the tank into the bowl.

Float Ball

A ball connected to the ballcock that rises and falls with the water within the tank. It regulates the ballcock as needed.

Float valve

A type of control valve that shuts off water at a predetermined level or capacity. A float valve controls the water in a toilet tank. One form of operation has a hollow ball, mounted by a connecting rod to the valve. As the ball rises with the water level, the valve closes until water flow is completely stopped.

Floor Cleanouts

A readily accessible opening installed in the floor off of a horizontal waste line to accommodate drain cleaning equipment to remove potential blockages.

Floor Drains

An opening in the floor used to drain potential liquid waste from the floors into the drainage system. Floor drains are most commonly seen in basements, core toilet rooms, janitor’s closets and mechanical rooms.

Floor Flange

a fitting that connects a toilet to the sewer line; also known as a closet flange

Floor Sinks

A receptor installed in a floor that receives drainage from indirect waste lines. Floor sinks are often glazed with porcelain or epoxy to inhibit bacterial growth and to make it easier to clean and maintain.

Flush valve

Located at the bottom of a toilet tank, the flush valve discharges the water from the tank into the bowl when the toilet is flushed.


toilet valve that automatically shuts off after it meters a certain amount of water flow; Flushometers are usually found on commercial grade toilets

Flushometer Tank System

A toilet flushing system that uses water pressure to flush instead of the traditional gravity flushing system.

Flushometer Valve

There are several different type of flushometer valves on the market the diaphragm type valve invented by William Sloan and the Sloan Valve Company in 1906 is the undisputed leader in Flush valve production and market use. However all flushometers are designed to do the same thing and that is to deliver a measured amount of water to a fixture to flush out waste, i.e. a water closet or urinal. Both a diaphragm and a piston type flush valve operate by using water pressure to actuate the valve.


Plumbers flux comes in the form of paste and it is brushed on copper or brass pipe and fittings to remove oxides and other coatings for the metals before joining. Oxides make soldering difficult. Upon heating the pipe/fittings and flux, the flux will clean and float away any oxides or particulates.


Abbreviation for Female National Pipe Thread Taper.


The amount of floor space taken by an appliance.

French Drain

A covered ditch with a layer of stones or other material.

Friction (Water Piping)

It is the resistance between to objects in contact with one another. In a water piping system it is the friction that occurs between water and the walls of the piping. Water that comes in contact with the walls of the pipe actually moves slower than water in the center of the piping. We call that friction loss in the piping trades.

Friction Clamps/Riser Clamps

A friction or riser clamp is used in the plumbing and mechanical trades to support vertical piping at each floor. The hanger device is place around the piping and tightened with bolts which prevents the piping from slipping. Riser clamps have wings or ears that extend out from the pipe to span the opening in the floor to accommodate the piping being braced.

Friction Loss

Pressure lost in a pipe due to turbulence created by water traveling through pipe.

Frost Proof Hose Bibbs or Sillcocks

A faucet that delivers water to locations (usually outside) for watering landscaping or grass, washing vehicles or general cleaning. When the hose bibb is designated as “Frost Proof” it is usually has an apparatus which allows ice to expand without damaging the unit or connected supply piping.


Female sweat connection

Futures (Vent, water and waste)

Futures in plumbing are fittings and or piping installed and capped to accommodate “future” plumbing expansions. i.e. an office building is being built and the owner is taking the entire space. However, at some point the owner may want to divide the building to accommodate possible tenants or expansion of existing office space. Futures would minimize the contruction to rehab, expand or reconfigure the existing plumbing systems.


Flammable Vapor Ignition Resistant. Gas fired water heaters sold as of July 1, 2003, per the American National Standards Institute (ANSI), must include features to resist possible ignition of flammable vapors outside of the water heater combustion chamber.




(Gallons Per Minute) A unit of measurement used by plumbing material manufacturers to convey performance or measure capacities of a fixture, water piping and or waste piping.

Gallons per flush (GPF or gpf)

A measure of the total volume of water required to flush a water closet or urinal, measured in gallons.

Gallons per minute (GPM or gpm)

A measure of the rate at which water flows through a fixture or fitting at a certain pressure. It is measured by the number of gallons flowing from the device in one minute at a given water supply pressure.

Galvanized steel (piping)

A type of steel water piping, coated with a zinc compound. The zinc acts as a sacrificial metal, slowing down the corrosion process.

Garbage Disposals

An electrically powered plumbing appliance installed on the outlet of a kitchen sink that is used to grind up leftover organic waste so it is easily rinsed away by LOTS OF WATER. Garbage disposal are manufactured in several different price points which include better build quality, sound deadening materials and features. Commercial versions are also available.

Garbage disposal

An appliance attached to the drain system, usually under the kitchen sink, that chops up food waste, allowing easier flow through the drain system.

Gas Cock

gas valve installed on main gas line and on a gas appliance to allow the gas to be shut off when necessary

Gas Control

A piece of equipment that controls gas pressure on a water heater.

Gas Piping

The piping used to deliver propane or natural gas to a home and it’s gas powered appliances in the home i.e. stove, oven, and clothes dryer.


A Gate manages the flow in a conduit, pipe, or tunnel.

Gate Diverter

A lever on a tub that activates the diverter valve.

Gate Valves

The gate valve is typically operated by a wheel handle and that handle lifts and lowers a metal disc or wedge cutting off or opening the flow of water. A gate valve should not be used to throttle or regulate the flow of water. Gate valves are usually described as rising stem sometimes called an OS&Y (Outside Screw and Yoke) or non-rising stem. OS&Y valves are used in situations were it is beneficial and sometimes safer to be able to see if the valve is in the open or closed position by seeing whether the stem is visible or fully seated.

General Liability Insurance (GL Insurance)

A standard insurance policy issued to businesses but in this case plumbing and mechanical businesses to protect against liability claims generating from the operations the business performs this includes employee negligence. This is usually coupled with Workers Compensation Insurance to form a firms commercial insurance package.


Gallons Per Flush. Today’s toilets, per federal law, are only allowed to deliver 1.6gpf or less. In many years past, toilets flushed as much as 7-8gpf.


Abbreviation for Gallons Per Hour.


Abbreviation for Gallons Per Minute.


Gallons per minute. Usually used when describing how many gallons of water a fixture uses to operate.

Gravity Operated Toilet

a toilet that relies on the natural downward pressure of water in a toilet tank to flush the toilet effectively; most toilets in American homes are gravity operated

Gravity Sewers

All sewers work by by gravity. However this term is used by plumbers to describe a house drain which runs under the basement floor and receives the discharge from soil, waste and other drainage from pipes within the building. It is almost always used to describe a sewer when a home is affected by sewage backing up from the city sewer during extreme rain fall. The solution to a gravity sewer would be to run the sewer over head. (See Over Head Sewers)

Gravity-fed toilets

The most common type of toilet in the United States, gravity-fed toilets rely on the force of gravity to flush the toilet effectively. The natural force of water dropping down from the tank scours the bowl clean and forces water and waste quickly into the trapway.

Gray Water

is defined as water generated by sinks, showers, bathtubs and clothes washers. It does not contain waste water from water closets, urinals, kitchen sinks or waste from dishwashers.

Gray Water Waste Pipe System

Is the piping and storage system that collects waste water generated from hand sinks, showers, bathtubs and clothes washers. Because over 60% of all household water usage can be labelled as gray water systems have been developed to recycle this water and reuse. Graywater piping is purple in color so it will standout amongst other piping systems. There are three separate steps in the graywater recycling process and they are as follows. 1) Collection – Graywater and black water wastes systems are piped separately. The graywater is harvested is storage tanks. 2) Treatment – Depending on the use the waste water is filtered. There are a multitude of ways to implement the filtration process but the most common is using physical media. 3) Disinfection – The filtered graywater is disinfected using UV, chlorination or iodine or a combination of the aforementioned.

Grease Traps or Grease Separator

A device designed to cause separation and retention of oil and/or grease from liquid wastes. Grease separators are most commonly used in commercial kitchens, restaurants or apartment buildings. Periodic grease removal maintenance needs to be done in order to maintain performance levels.

Green Plumbing

Is any type of plumbing that promotes conservation of water and or electricity, such as: Gray Water, Low Consumption Plumbing Fixtures, Rain Water Harvesting, Solar Hot Water, Tankless or Self Condensing Hotwater, Waterless Urinals.




Abbreviation for “horse power.”


Abbreviation for “hose threads.” Garden hose threads are different than standard pipe threads. They are much more coarse and are 0.75 – 11.5 NH (normal hose). The 0.75 is the nominal diameter (3/4 inch) and the 11.5 is the number of threads per inch.

Hair Separator or Hair Trap

these are installed on lavatories or sinks in beauty salons or barber shops and they catch link or hair from entering the waste piping. They are equipped with a removable basket that must be cleaned regularly to maintain proper flow. They also have a secondary purpose as they safeguard against losing jewelry if dropped down the drain.

Hand Held Shower with Slide Bar

A shower head that is attached to a flexible hose and can be moved up or down on a stationary slide bar or removed from a holder and used to rinse the hair and body. Originally designed as necessary item for the elderly and handicapped it has now become a premium upgrade in home showers.

Hand or Sink Auger

This is a coiled flexible cable that is contained inside a metal cannister and has a self feeding auger bit to dig through blockages in small diameter piping. The cannister is usually equipped with a handle and a knob so you can turn the rod cleaning the pipe of debris.See the full sink auger definition.


A showerhead designed with a handle that is connected to a water supply via a flexible hose.

Hard Water

Hard water is a condition caused by minerals dissolved in water. There are many minerals that can be dissolved in water but the primary are Calcium and Magnesium. 85% of the water in the U.S is considered hard water. Some of the symptoms a homeowner will experience if they have hard water will be spots on their dishware, rings around the bathtub, scale build-up on shower heads and aerators on sink faucets. Hard water also reacts with cleaning products and detergents reducing it’s effectiveness. Hard water treatment comes in several forms the most common is an ion exchange based water softener.


The water pressure exerted by gravity (2.31 feet of height means/delivers one pound of head). Also, slang for toilet.

Head Pressure

It is the difference in elevation between two points of water expressed in weight of a given height of a column of water. The pressure at the bottom of the column of water is greater than at the top of the column and that pressure is independent of the volume of water present. For instance the “head pressure” of a column of water that is 15ft high in a 3″ pipe is the same as if the pipe were 3ft in diameter.

Heat Exchanger

A heat exchanger is an apparatus such as coiled copper or stainless steel tubing that is submerged in a tank of water. That coil is used to transfer the heat from the liquid in the tubing to the water in the tank by way of the metal surface.

Heat Traps

On water heaters a heat trap allows cold water to flow into the the heater but prevents hot water from flow out of the tank when not in use. Having heat traps provides energy cost savings by preventing heated water from escaping the tank so it doesn’t have to be brought up to temperature again.

High efficiency toilet (HET)

A toilet with an average water consumption of 1.28 gallons per flush or 4.8 liters per flush, when tested in accordance with a standard or product specification, such as the United States Environmental Protection Agency’s WaterSense program. HETs use 20 percent less water than mandated by the Energy Policy Act of 1992, which lowers utility bills and reduces the strain on septic systems. HETs are eligible for special rebates in many drought-prone areas. They are available as single flush gravity toilets, dual-flush gravity toilets or pressure-assisted toilets.

High efficiency urinal (HEU)

A urinal that uses a half gallon or less of water, half the amount allowed under the by the Energy Policy Act of 1992, Contributes to lower utility bills, while reducing the burden on septic systems. HEUs are sometimes thought to be waterless, which isn’t true. Waterless urinals are one type of HEU, but there are also urinals that use water and still meet higher efficiency standards.

Hoar Frost

In plumbing it is the frost that forms on vent stacks from water vapor coming in direct contact with air that is below freezing. The thought is that with continual sub freezing temperatures that layer upon layer of hoar frost can eventually close off vent stacks compromising the proper function of the waste system in a home or building.

Horizontal Branch

Drain pipes that run laterally. They run from plumbing fixtures to waste stacks in a building or in the soil.

Horizontal Run

the horizontal distance between the point where fluid enters a pipe and the point at which it leaves


A flexible rubber or plastic tube for carrying water. Garden hoses have special fittings to connect to the hose bibb and attachments.

Hose bibb

External or internal valved water fitting to which a water hose is connected. It is also called a spigot or faucet. Internal hose bibbs are found in the laundry area for washing machine hook up.

Hose Bibbs or Sillcocks

A faucet that delivers water to locations (usually outside) for watering landscaping or grass, washing vehicles or general cleaning.

Hot Tap

The process of tapping into water main or water supply line while the line is still active and in use. The process was developed to minimize down time to other homeowners or building tenants during maintenance, rehab or new construction. The alternative to hot tapping or pressure tapping would be to shut down and drain down the affected section of piping so the work could be completed.

Hot Water Return Piping

Hot water return piping is piping connecting the end of a run of plumbing fixtures and/or appliances back to a hot water source i.e. a water heater or boiler. Most times a hot water return line is installed with a recirculating pump to insure hot water is always recirculating through the hot water supply piping. Keeping hot water recirculating through the line dramatically cuts down on the time it takes to get hot water to a fixture. The average family wastes 12,000 gallons per year waiting for hot water.


Former manufacturer. Commonly means stainless steel sink frame.

House Drain

The House Drain is the lowest part of the drainage system piping that receives all of the soil and waste discharge from other drainage piping within a home or building and discharges it to the house sewer that begins 5ft outside of the building.

House Pumps

(Domestic Water Booster Pumps) Variable Frequency or constant speed. Uses in commercial and residential. Most plumbing fixtures and equipment need a minimum amount of water pressure to function properly, a house pump or booster pump takes incoming water and increases the pressure to accommodate the water demands of a private residence or a commercial building.

House Sewer

The part of the horizontal piping of a plumbing or drainage system that extends from the house drain to it’s connection with the main sewer or other place of sewage disposal. So the piping that connects the interior sewer to it’s connection to the municipal sewer.

House Trap

Although there are many homes that still have a house trap in use they are generally frowned upon. A house trap is a trap installed on the house drain to prevent sewer gases and vermin from entering a residence or commercial building. The biggest issues with house traps are that if the trap is ever compromised the entire building is susceptible to sewer gases.

Hub and Spigot Soil Pipe

Hub and spigot soil pipe is usually made of cast iron and is used in sanitary drain, waste and vent, sewer and storm drainage applications. The pipe and fittings have a bell on one end and are plain on the other. The plain end is inserted into the bell or spigot end and the joint is sealed using a rubber soil gasket or braided oakum and lead.

Hubless (No-Hub)

A drainage pipe made of cast iron that utilizes neoprene gaskets and clamps.


Hot water

Hydraulic Pressure

The pressure applied by a liquid against an object. Most liquids cannot be compressed into a small area like air can. Therefore when a liquid is applying pressure to an object the liquid will find it’s way around the object or if need be through the object.


A system that transports heat through circulated water.




Abbreviation for “inside diameter.” In plumbing, most pipes are sized by “nominal” (approx.) I.D. which means that when plumbers say 3/4″ pipe, for example, it generally means that the outside diameter is wider than 3/4″.

IAPMO Plumbing Code ( The International Association of Plumbing and Mechnical Offiicials) or UPC (Universal Plumbing Code)

This is the most update and accurate set of current plumbing practices, it is produced by plumbers and mechanical engineers. It includes installations for potable water, building water supply and distribution, waste drainage and vent piping, sewer mains and plumbing fixtures. It also defines material and code approved joining methods.

Ice Maker

A plumbing appurtenance that can be stand alone or part of a refrigerator and is used to make ice for beverages or for therapeutic uses. An ice maker needs both a water connection and a waste connection for the discharge of condensate waste.

Indirect Waste Pipe

Waste piping from a plumbing fixture or appurtenance that isn’t connected directly to the waste drainage system of a home or building but instead it drains into the drainage system through an air gap and into a fixture, interceptor or receptacle like a floor sink which is properly trapped and vented.

Indirect Wastes

A waste pipe that discharges gray water by discharging it into a plumbing fixture.

Instantaneous Water Heaters

An instantaneous water can be broken down into the following two categories. 1) Point of Use – A point of use water heater is installed at or near a plumbing fixture or battery of fixtures and it used to service those fixtures alone. Their capacity to flash heat water is limited. They are mainly used in situations where it is too difficult to tie into and existing hot water source or a small bathroom or sink has been added and has a limited need for hot water. 2) Tankless Water Heaters – Both of these heaters are tankless however, when someone refers to a tankless water heater they usually mean a high capacity heater used to serve multiple locations in a home or business. A tankless heater flash heats water on demand by pulling water through a heat exchanger. There is no hot water storage although one can be added if the application calls for additional capacity. Tankless heaters are generally thought of to be much more efficient than traditional tank type water heaters. However, real world use has clouded that belief.

International Plumbing Code or IPC

The International Plumbing Code was first adopted in 1995 and it was really a combined effort as representatives from BOCA, ICBO and the SBCCI were all used to produce an all inclusive set of rules and regulations based on existing model codes. The IPC was established to set standards to adequately protect the public health and safety but not necessarily increase the cost of building and fabrication. There are several states and municipalities that have adopted the IPC as their plumbing code. The IPC can be adopted internationally.


The lowest point of the inside of any type of horizontal waste, vent or water piping.

Invert Elevation

Closely associated with the above, the invert elevation is really the cornerstone elevation for the mechanical and in particular the plumbing trade. It is the lowest inside point of any pipe at a certain location. Knowing invert elevations are extremely important for laying out waste piping runs. Mistakes can cause mistakes ranging from sewer piping not having enough pitch to waste piping being removed because it is above the ground or hanging below a drop ceiling.


Generally an abbreviation for “iron pipe size.” Sometimes it means male pipe threads.


Generally an abbreviation for “iron pipe thread.” Sometimes it means male pipe threads.

Iron Filter Tank

Any device that removes dissolved or undissolved iron from potable drinking water. Some smaller units can be installed in line with your water main and need to be maintained by changing a removable media. There are also iron filters that can handle removing iron for the whole house using media that can be recharged relieving the homeowner of having to change the filter once a month. See Charger Water Treatment for their solutions on treating potable drinking water.

Island Vent

(See Loop Vent)

Isolation Valves

Any type of valve installed on the potable water system that isolates a section of a building, a battery of bathrooms or plumbing mechanical equipment i.e. a house pump. Isolation valves allow plumbers positively shut down the water supply to the aforementioned so work can be performed without shutting down the water supply to the entire building.




J type hooks are used in just about every industry. In the plumbing industry they are made of plastic, steel or copper plated and come in different sizes to accommodate different sized pipe. They look like the letter “J” and are usually nailed or screwed into a wooden or steel joist to hang waster, vent and water piping.


A toilet feature that directs water into the trapway to begin the siphon action.


A johnni-bolt or closet bolt is used to mount a toilet bowl to the closet flange.


A plumber who has completed apprenticeship requirements. Ongoing training is still required, although more responsibility is given to the journeyman. Normally the journeyman must hold that license for 4 to 5 years before progressing to the master level.



Kafer Fitting

A cast iron drainage pipe that attaches to the existing case iron lines.

Kitchen Sink Faucet with a Pull-Out Spray

Kitchen sink faucets are manufactured with or without a spray mechanism. In the last 20 years most of the faucet manufacturers have come out with kitchen faucets with a sprayer that pulls out from the spout. The spray head will have a function button that when depressed will switch the function between hard spray or aerated flow. Since their inception they have become extremely popular due to the fact that you don’t have to have a side spray taking up space on the faucet deck to have the same functionality.

Knockout Plug

PVC test plug.




See plumbing fixtures

Lavatory (Lav)

While sometimes used by the general public to mean a bathroom or washroom, the plumbing industry uses lavatory to mean a bathroom washbowl or basin permanently installed with running water. The plumbing industry uses the term “sink” in reference to kitchen sinks.


In the case of plumbing systems, leaching refers to the process of dissolving a soluble component out of a constituent material at a wetted surface. Materials commonly leached into drinking water from water distribution systems include copper, lead, and nickel.

Leach Field

For the purpose of emptying treated waste, a porous soil with septic tank lines running through it.


One of the basic elements (Pb), lead is a soft metal that has been used in plumbing systems for thousands of years. The word “plumbing” derives from the Latin word for lead, plumbum. Lead has a unique ability to resist pinhole leaks, while being soft enough to form into shapes that deliver water most efficiently. Its softness and malleability were for a long time highly desirable properties for manufacturing everything from pipe to paint. Lead is a neurotoxin that can accumulate in the body in soft tissues, as well as bone.

Lead and Copper Rule (LCR)

A United States Environmental Protection Agency regulation dating back to 1991, LCR requires water systems to monitor drinking water that comes through faucets in homes and buildings. If lead concentrations exceed 15 parts per billion (ppb) or copper concentrations exceed 1.3 parts per million (ppm) in more than 10% of homes and businesses sampled in a regional plumbing system, the system must take actions to control corrosion and leaching. If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health, including the possible replacement of plumbing system piping.

Lead Flashings

thin sheets of lead used to water proof vent stacks through the roof. A tube of lead is made slightly larger in diamter than the piping being flashed, that tube is welded on to flat piece of lead. The lead flashing is installed over the vent through roof increaser and the end of the lead is pounded down inside the piping. The roofing material is placed over the flashing and around the pipe and is sealed. Vent flashings are also made of rubber membrane.

Lead Pan

Lead pans have been used in plumbing for a number of reasons. As a durable malleable material to use to water proof a shower or mop basin where stone or tile is being used as flooring, as a drain pan used to catch water from a water heater should it start to leak. You being with a flat piece of sheet lead

Lead Pick

This a tool that looks like an awl, with a metal tip bent at a 90° angle or like a hook, that is used while drilling out an old lead joint, to pick out the loose lead and oakum.

Lead Pot and Ladel

Used primarily to pour lead and oakum joints for waste and vent piping. A lead pot is made of cast iron and lots similar to a cooking pot. It is made to sit securely on top of furnace that attaches to plumbers propane tank. Lead is placed inside the lead pot and is heated until melted. A cast iron ladel is used to extact the molten lead from the pot so it can be poured into a hub. Molten lead does not stick to cast so it can be poured easily.

Lead Water Services

Lead was the material of choice for water services in all major municipalities until the end of the 1960’s. Because lead is malleable and utterly non-corrosive it was a go to for plumbers for the better part of a century. It wasn’t until we became aware of the harmful effects of lead poisoning that lead services were discontinued. The funny things about lead water services is that a hard scale barrier forms over the piping exposed to potable water so quickly that there is no measurable leeching however I suppose it’s better to be safe than sorry.


Under section 1417(d) of the Safe Drinking Water Act, “lead free” is defined as being no more than 0.2 percent of materials used in solders, and no more than 8 percent of materials used to manufacture pipe, fittings, and well pumps.


A leader is a pipe that carries rainwater to the ground or sewer.

Licensed, insured and bonded

Three business certifications that a plumbing service should have to do business. Licensed means that the plumber has passed regulatory requirements of the governing body. Insured means that the plumber has obtained insurance to cover employee injuries and damages on the jobsite. Bonded means that the plumber has obtained additional insurance through an outside agency in case of extenuating circumstances, like the company going out of business or an employee theft on the jobsite. Certain jobs, such as work being done for a government or state agency, require bonds.

Liquid Waste

Any liquid discharge from a plumbing fixture that does not contain human or animal waste matter.

Lock Nut

A nut that joins two pipes together.

Loop Vent

Some times this is referred to as an island vent because if you do vent your island you’d use a loop vent. A island loop vent begins at the discharge from island sink using a sanitary tee. The vent rises up above the discharge of the drain then drops back down and connects back to the drainage system below the floor. A loop vent in a commercial application has a different meaning; it is a single vent pipe connected to the horizontal drainage piping that receives the discharge from one or more unvented fixtures. The single vent pipe rises above the overflow level of the highest unvented fixture and the single vent is connected back to the vent stack. Basically this is a way to vent a battery of fixtures using a single vent pipe.


In the plumbing industry, low-flow fixtures and fittings refer to plumbing products that meet the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term “low consumption.”


Low water cut off.




All branches connect to this main water supply.

Main drainpipe

The piping where the dwelling’s drain piping system enters the septic system or underground drainpipe.

Main Line

the primary line that supplies water from the water company’s meter at the street up to the point where it enters the home; all other supply lines in the home branch out from this main line

Main Pipe

The central pipe line to which all other branches are connected. This covers all plumbing piping systems i.e. waste, vent and water piping.

Male Threads

Male threads thread into female threads. Female fittings openings are larger than male fittings. Male fittings fit into/inside female fittings.

Malleable Fittings

A pliable fitting made of metal.

Man Hole

A circular cover usually manufactured from cast iron that is part of a larger concrete structure used for easy excess to any number of below grade plumbing equipment. i.e. below ground valves, ejector or grinder pumps. A manhole can also be used as an access point for rodding and drain cleaning equipment on storm and sewer lines.


A type of fitting that connects branches to the main.

MaP Testing

A voluntary test protocol for toilets that measures the ability to remove solid waste, also referred to as “bulk.” Cooperatively developed in 2003 by water utilities and water-efficiency specialists in the United States and Canada, it uses soybean paste (miso) as test media, in an effort to replicate “real world” waste. The test is conducted by successively increasing the amount of test media that is flushed until the toilet is no longer able to reliably or completely remove the media from the bowl. Results are reported as a MaP score, which is related to the number of grams of a test media that a toilet can adequately flush.

Master plumber

A plumber who has completed both the apprenticeship and journeyman phase. A master plumber usually has ten to fifteen years of experience and must pass a state plumbing exam, including tests on plumbing codes and practices. The master plumber is responsible for business operations, planning and bidding on plumbing jobs.

Mechanical Joints

definition, materials used, types of mechanical joints. Any type of pipe and fitting joining method that ensures a water tight seal using the following: gaskets, couplings, grooved fittings and couplings, nuts and bolts, etc. The following are examples of mechanical joints: No-Hub Couplings, Mission Couplings, Victaulic Grooved Fittings and Couplings, Gruvlok Grooved Fittings and Couplings, Flanged Fittings using nuts, bolts and gasket kits.


The moving part components of plumbing, heating, and cooling systems in a building.

Mechanics Lien

A form of legal protection afforded to contractors and suppliers obtained as collateral against unpaid bills. When enforced any real estate or property such as a home or commercial building can be sold to pay off past due bills. As a mechanical contractor you should always protect your lien rights. The time for filing an Intent to Lien is different from state to state but usually you have 90 days from the performance of work to file an Intent to Lien. Once that time passes you will be forced to litigate but your lien rights will expire.

Metered toilets, or metered flush

A toilet with a mechanism that delivers a precise, non-variable amount of water with each flush.


Abbreviation for male hose threads.

Mini-Widespread Faucet

A style of lavatory faucet that has a separate spout and handles but fits on a lavatory with a 4″ spread and opposed to a widespread faucet which fits on a lavatory with an 8″ spread.


Abbreviation for male pipe threads.

Mixing Valve

A plumbing valve that mixes hot and cold water and delivers them at a specific temperature.

Molded Stone

Molded stone is most commonly used for laundry tubs and it is really used to describe a fiberglass product impregnated with a calcium resin. It’s extremely durable while being low cost. Consumers may think the term molded stone is misleading however it’s a term that has been used in the plumbing industry for decades.

Multi-Stage Pump

A pump with multiple impellers.



National Plumbing Code

This is a standard code book for the plumbing industry that covers BOCA (Building Officials and Code Administrator International) and UBC codes highlighting specifications and best practices and procedures for installation and standard plumbing materials

National Primary Drinking Water Regulations (NPDWRs, or primary standards)

Legally enforceable federal standards that apply to public water systems. Primary standards limit the levels of contaminants in drinking water. A 1996 amendment to the Safe Water Drinking Act (SDWA) requires that the United States Environmental Protection Agency establish a list of contaminants every five years that are known or anticipated to occur in public water systems and may require future regulations under the SDWA.


A short piece of pipe threaded on both ends used to join two threaded fittings.

No Hub Soil Pipe

A type of pipe normally made of cast iron, without hubs, joined with no hub couplings

No-Hub Connector

a connector for no-hub iron pipe consisting of a rubber sleeve and a stainless steel band secured by hose clamps. Or a a neoprene sleeve with two adjustable steel bands that is used for connecting dissimilar materials (for example, when connecting new plastic pipe to an existing cast-iron drainpipe.) Usually used in older homes.


Size used for identification only; not literal dimensions. Used to identify pipe and fitting sizes in plumbing. Refers to the inside diameter of the pipe which can vary by thickness of the pipe. The outside is a constant size. For copper pipe the outside diameter is always 1/8″ larger than the nominal size. Example: 1/2″ nominal is always 5/8″ O.D.


Abbreviation for National Pipe Straight Threads Standard (IPS)


Abbreviation for National Pipe Straight Mechanical. Similar to garden hose threads NPSM fittings must be used with a washer between the male and female fittings to create a tight leak-proof seal. The threads themselves will not seal liquid from leaking at the fitting.


Abbreviation for National Pipe Tapered Threads Standard (FIP, MIP). NPT is the United States standard for tapered threaded fittings and pipe. Manufacturers are to follow this standard when fabricating or manufacturing pipes and fittings used for plumbing.


Founded in 1944, NSF International is a not-for-profit, non-governmental organization that develops standards and product certifications in the area of public health and safety.

NSF/ANSI Standard 60

A standard related to chemicals used to treat drinking water. Developed by NSF and conforming to the ANSI voluntary standard, the standard was accepted by the NSF board in 1988 to evaluate products, such as softeners and oxidizers, to assure that usage amounts safeguard the public health and safety.

NSF/ANSI Standard 61

A standard related to products that come in contact with drinking water. Developed by NSF and conforming to the ANSI voluntary standard, the standard was accepted by the NSF board in 1988 to confirm that such products will not contribute excessive levels of contaminants into drinking water. Most U.S. states and many Canadian provinces require products used in municipal water distribution systems and building plumbing systems to comply with Standard 61.




Used around valve stems, a rubber washer that creates a watertight seal.


Abbreviation for Outside Diameter.


Oakum woven hemp rope that has been treated with a waterproofing agent. It caulks bell and spigot pipe and fitting joints.


Abbreviation for “outside diameter.” The measurement of the diameter of the pipe as taken from the outside edge.


Abbreviation for “original equipment manufacturer.”

One-Piece Toilet

The toilet tank and bowl are not separate, but make one single fixture. Less common and usually more expensive, but generally a more stylish toilet.

Outdoor faucet

A hose bibb located outside the home or building. The connection threads will usually be designed to accept hose fittings.

Outlet Sewer

An outlet sewer is a pipe section that runs between a septic tank and drainage field in a septic system.


The difference between the most wide OD and the most narrow OD on a pipe or tube. Found be subtracting the minimum outside diameter from the maximum outside diameter on a pipe.


A type of drain used to prevent overfilling of a fixture. For example, the small hole near the top of the bathroom sink connects to the sink drain, preventing the basin from flooding onto the floor.

Overflow roof drains

See Plumbing Mechanical Equipment

Overflow Tube

If the ballcock malfunctions this vertical tube inside the toilet tank will direct water into the toilet bowl. This is the part that can sometimes make your toilet sound like it is constantly running, which is an indication that there is a problem with your ballcock.




A sink drainpipe designed in the shape of a “P.” It runs from the sink and down through the floor to the main drain piping. The shape is designed to trap a small quantity of water in the pipe, preventing sewer odors from entering the dwelling. An S-trap is similar, but exits the room through the wall instead of the floor.


A material used on faucets that prevents leaks.

Packing Nut

A nut that keeps the faucet in position and holds the packing material.


Polybutylene, flexible plastic tubing formerly used in water supply systems where allowed by code.


Common finish abbreviation for polished brass when referring to a fixture’s part number

PB (Polybutylene)

A type of flexible, plastic tubing used in some water supply systems.


Abbreviation for polyethylene. Most common plastic made. Plastic used for many types of water and gas piping.

Peak Hour Demand

The peak hour demand is the time of day when hot water demand is at its climax.

Performance-based product standards

These standards define a desired outcome from products, related to what they do, rather than how they are made and what they are made of. These standards typically prescribe a means for determining whether the product delivers to the standard. For example, a performance-based product standard for fittings would specify the maximum amount of alloy materials, such as lead, that may be leached into the drinking water.

PEX (piping)

A newer type of flexible tubing, used to replace the potable water piping in a dwelling or building. PEX tubing uses hose barb connections and compression rings, thus it requires less labor to install. It installs easily around corners, omitting the need for the elbow fittings needed when installing copper or galvanized piping.


The amount of hydrogen ion concentration in water. Measurement used to determine acidity or alkalinity in a given substance.


Plumbing Heating Cooling Contractors Association

Pilot light

A small gas flame used to ignite a larger burner when a gas valve is turned on. If the pilot is always lit, it is called a standing pilot. On demand pilots are ignited by a sparking device when needed.

Pipe Bursting

The pipe bursting method is used in underground piping i.e. concrete or clay tile where the piping is too deteriorated to repair by other methods. A very strong cable is pulled through deteriorated piping and attached to a conical pipe bursting head, attached behind the head is the new piping. As the pipe bursting head is pulled through the old piping it is being broken up and the new piping is being pulled through the old pipe bed.

Pipe Dope

A nickname for a material that is applied to a threaded fitting to create a watertight seal.

Pipe threads

A spiral flute cut into the end of a pipe, allowing pipes to be coupled to fixture or pipe couplings. Pipe threads should have Teflon pipe tape, pipe thread compound or a combination of both applied to the threads to prevent leakage under pressure.


Unlike tubes, the measurement of a pipe (i.e. 2″) roughly references the inside diameter (ID) of the pipe and not the outside diameter (OD). A 2″ Sch 40 pipe actually has an OD of 2.375″, a wall thickness of .154″ and an ID of 2.067″.


Downward slope of a drain pipe in the direction of the water flow, also known as the “fall” of the pipe.


The act of performing plumbing work.


A technician that specializes in plumbing installation and repairs. Plumbers are usually licensed by the state or other governing authority, have been educated in various aspects of the plumbing industry and are qualified to make repairs or handle new installations. Plumbers may work on all types of plumbing or may specialize in certain areas, such as residential, commercial or industrial plumbing. They should be licensed, bonded and insured.

Plumber’s Putty

Pliable putty that seals joints between drains and fixtures,

Plumbing Fixtures

A device, appliance or “appurtenance” that is hooked up or installed to the potable water system which makes the potable water available to flush liquids or liquid born wastes either directly or indirectly into the waste system.

Plumbing Manufacturers International (PMI)

A not-for-profit trade association of plumbing products manufacturers. PMI member companies produce most of the nation’s plumbing products. Read more.

Plumbing Tree

A set of drain waste, vent, and supply lines that have been pre-fabricated.

Plumbing Valve

is any valve used to regulate the flow of water in a potable or human waste water system.


A cupped, rubber headed, suction device on a handle that is used to clear a clogged drain.


Point of connection


This is a soft, gray or blue plastic pipe that was widely-used from the mid- 70’s to the mid- 90’s across the nation. Since then it has become known that polybutylene deteriorates over time and leaks.

Pop-Up Assembly

The drain mechanism of a faucet installed on a lavatory. The drain stopper “pops” up and down.

Pop-Up Drain

A type of drain assembly that uses lavatory lift rod or bath overflow plate lever. When it is lifted, the pop-up drain closes for the purpose of retaining water.


A white ceramic ware that consists of quartz, kaolin, and feldspar. It is fired at high temperature on steel or cast iron to make the surface of some bathtubs, kitchen sinks and bathroom lavatories. Many times the word “porcelain” also refers to porcelain china which is a ceramic product with porcelain glaze.

Porcelain enamel

A coating used on metal fixtures, such as cast iron sinks and bathtubs. Ceramic material is fired at high temperature to form a vitreous porcelain film that is fused to the base metal of the fixture or fused to a ground coat. Porcelain enamel gives metal plumbing fixtures their colors and desirable glossy surfaces.


The opening in a burner head that allows gas or air-gas mixture to escape for ignition.

Positive Displacement Pump

The PD pump makes a fluid motion by containing a fixed amount and moving it into the discharge pipe.


In reference to water is that “potable” means it is drinkable water. Water that is suitable for human consumption.

Potable water

Water that is satisfactory for drinking, culinary and domestic purposes.

Power Flush System

Toilet flushing system that compresses water to provide a pressurized flush as opposed to a gravity flush. Power assisted toilets are more typically found in business or commercial settings.

Power Vent

Refers to mechanical venting in water heating. Generally (not always) water heaters that use power venting are more efficient than regular draft venting.


Parts per million. Used as a measurement of concentration.


Abbreviation for “Pressure Regulator.” Generally means water pressure regulator. Most codes require one if water pressures ever exceeds 80 pounds at any time on domestic potable water systems inside a structure.

Prescriptive product standards

These standards differ from performance-based product standards in that they attempt to achieve a desired outcome by specifying the characteristics, materials, performance and operability of products. For example, a prescriptive product standard for fittings would specify the maximum amount of alloy material, such as lead, that can come in direct contact with the drinking water.

Pressure Balance Valve

A shower mixing valve that automatically maintains balance between hot and cold water supplies by immediately regulating fluctuations in pressure. As a result the outlet temperature remains constant.

Pressure gauge

A measuring device used to determine the pressure in a piping system.

Pressure tank

Part of a well pump assembly that reserves water for use. The tank contains a bladder that puts pressure on the water in the tank. When a faucet or spigot is opened, the pressure forces the water through the piping. Through gauges and switches, the tank monitors the water pressure and starts the pump when pressure lowers to a predetermined level. When the valve is closed, the pump continues until the water has reached the upper pressure limit.

Pressure Tubing

A pressure tube conducts fluids under pressure or at high temperatures.

Pressure-assisted toilets

A toilet that uses a compressed-air device to enhance the force of gravity used to clean the bowl when the toilet is flushed.

Pressure-balancing valve

Also known as a pressure-compensating valve, this device is designed to reduce the risk of thermal shock and scalding while showering. Required by code in most areas of the United States, a pressure-balance valve senses the hot and cold water pressures coming in from the supply line and compensates for variations to maintain the water temperature. Such variations can occur when a toilet is flushed or a washing machine started while someone is showering.

Priming Jet

The opening in the toilet bowl that allows the flow of water from the tank, designed to push waste through the trapway.

Private Sewer

Any sewer that serves one or more buildings that is privately owned and is not directly controlled or maintained by a public entity.

Product standards

Established by research and consensus, product standards define what products are made of, as well as how they perform. For plumbing products, product standards govern the characteristics, materials, performance and operability, as well as how products need to interact with other plumbing-system elements. For example, a product standard for fittings would define the alloys and the amounts that can be used in their manufacture.

Proposition 65

Also known colloquially as Prop 65, California’s Safe Drinking Water and Toxic Enforcement Act of 1986 requires companies to post notice of chemicals in products that can be released into the environment and have been determined by the state to be a cause of cancer. In early 2008, the list included 775 chemicals. Prop 65 impacts residents in other states when they receive such notices in purchased products, such as bathroom faucets. Companies will often post the notification on all products, rather than incur extra costs to isolate products sold only in California.

Proximity valves

An electronic valve for plumbing fixtures and fittings that enables them to be operated without being touched. Similar to auto-open doors and light sensors that are activated by movement, proximity valves deliver the benefits of being both barrier-free and sanitary to use. Proximity valves can operate toilets, urinals and faucets.


Pressure reducing valve.

Pressure Reducing Valve

a special valve installed on the main water line coming in to the home so that water entering the valve from municipal mains is constricted within the valve body. It reduces water pressure coming in to your home from the high level used by the water company down to a level that can be used in your home without damaging your fixtures.


Pounds per square inch. Used as a measurement of pressure inside a given object.

Public Sewer

Any common sewer controlled and maintained by a city, county, state or federal government.

Pull Out Spray

When referring to a kitchen faucet this is a retractable hose/sprayhead. We’d like to mention that hoses used with a pull-out spray can turn out to be a high replaceable item. If you have a pull out sprayer be sure to pull it out straight each and every time. Do not kink the hose because if you do, no matter what brand, you could be ordering replacement hoses frequently.


Polyvinyl chloride. A rigid white or cream-colored plastic pipe used in non-pressurized systems, such as drainage, waste, and vent systems.


Physical Vapor Deposition (used mostly with polished brass or gold finishes). This is a modern plating process used in faucet manufacturing. Vaporized zirconium reacts with nitrogen and other gases to form a VERY durable plated surface. Unlike former days when polished brass would easily tarnish over time, polished brass finishes with PVD are extremely durable and won’t generally tarnish or discolor.

PVD finishes

PVD stands for Physical Vapor Deposition. This process, which occurs in a vacuum chamber, electrostatically applies extremely thin, but extremely dense coatings of exotic metal alloys onto fittings. The resulting finish is state-of-the-art in durability, scratch-resistance and lasting beauty for faucets. A wide range of finishes with PVD is possible, including chrome, nickel, brass and bronze.





Rain barrel

A tank or container used to collect rainwater or roof runoff water for various uses.

Rate of Flow

This is a term used to describe the volume of moving water as it related to a time period. The most common measurement used in plumbing is gallons per minute (GPM) or gallons per hour (GPH).

Rated Storage Volume

Quantity of water stored in a tank.


A grinding tool that levels valve seats in faucets to improve the valve stem fit.

Recovery Capacity

The amount of water in gallons/hour raised to 100 degrees at a given thermal efficiency.


A fitting that connects pipes of different sizes together.

Refill Tube

Carries water from the ballcock to the overflow tube after the siphon break in order to refill the toilet bowl.

Relief Vent

Extra vent added to a vent line or drain line to keep the air pressure within the system in balance with the outside atmosphere. This will help keep the traps from air-locking or losing their trap seal. Required when a drainage stack extends 10 or more stories above the building drain. Such drainage stack shall be served by a parallel vent stack that connects to the drainage stack at each fifth floor. Relief vents of these types of drainage stacks shall not be less in diameter than either the drainage or vent stack, whichever is smaller. Also required when combination waste and vent systems are used for multiple floor or shower drains, floor sinks in markets, work tables in schools or similar applications where the fixtures are not close enough to walls to allow for conventional type venting. Relief vents for combination waste and vents shall not be less than one-half of the inside cross sectional area of the drain pipe it will serve.

Reset button (garbage disposal)

A button on the bottom of the garbage disposal used to reset an overload device on the disposal. The overload trips when the disposal becomes locked up, preventing motor damage and potential fire hazards.

Return Circulation System

A system that eliminates the waste of hot water for long runs; this system also adds storage.


A pipe that connects with a vent system, used to vent a fixture trap.

Reverse Trap Water Closet

A water closet that has a siphonic trapway at the back of the bowl.

Rigid Pipe

A pipe that transmits the backfill load to the foundation beneath the pipe.

Rim Holes

Small holes along the underside of the toilet bowl rim in which water flows out of, resulting in a rinsing of the toilet bowl’s inner surface.


An assembly that connects a faucet and water supply stop valve. It is also a name of a supply line that goes from one story to the next.

Roof Drain

a roof drain is a plumbing appurtenance installed on a building roof, inside a gutter or in a parapet wall to receive rain water. The water is routed to the building or structures downspout piping and discharged to a storm sewer or is allowed to splash on the ground. Please check your local plumbing codes to find out acceptable methods for the discharge of rain water.

Roof Flashing

Installed to prevent leaks, it is a sheet metal at the break of a shingled roofline, sewer vents, and flue pipes.


Installation into the proposed location of the drain, waste, vent, and supply lines.

Rough-In Dimensions

The measured length between the center of a waste/supply opening or fixture to a wall or floor.

Round Front

The standard shape of the front of a toilet bowl. Generally bout 2″ shorter than the optional “elongated” bowl.


A complete or secondary section(s) of pipe that extend from supply to fixture or drain to stack.



Saddle Valve

a valve mounted on a pipe run by a clamping device, or fitting that taps into the side of a pipe, used to make quick connection to an existing line to provide a water supply for a low-demand device.

Safe Drinking Water Act (SDWA)

The Safe Drinking Water Act (SDWA) is a federal law originally passed by Congress in 1974 to protect public health by regulating the nation’s public drinking water supply. Amendments were passed in 1986 and in 1996. The SDWA requires many actions to protect drinking water and its sources: rivers, lakes, reservoirs, springs, and ground water wells. SDWA authorizes the United States Environmental Protection Agency to set national health-based standards for drinking water to protect against both naturally occurring and man-made contaminants. Enforcement is accomplished through the National Primary Drinking Water Regulations.

Sanitary Fitting

Fitting that joins the assorted pipes in a drain, waste and vent system; designed to allow solid material to pass through without clogging.

Sanitary Sewer

A house drain or a house sewer designed and used to remove only sewage. Storm water need not apply. Believe it or not there are places around the country that separate the storm and sewage systems in a building only to let them combine outside the building to a combined sewer.

Sanitary sewer system

The system of drain piping that carries wastewater from the dwelling’s sinks, tubs and toilets to the city or municipality sewer system.

Schedule (SCH)

The “Schedule” designation tells you how thick the wall is for any size of pipe with the higher schedule numbers meaning a thicker wall. The most common schedules are Sch 40 and Sch 80, but the actual wall thickness varies depending on the size of the pipe.


Standard Dimension Ratio (SDR) used for determining the minimum wall thickness for pipe. SDR is found by dividing the outside diameter (OD) of the pipe by the wall thickness measurement. To find the minimum wall thickness of a pipe you simply divide the OD by the SDR.

Self-Rimming Sink

A sink with a built-in lip of the same material that supports the vanity top.

Septic field

The system of pipes that discharge bacterially treated wastewater from the septic tank and discharges it into the soil for natural decontamination.

Septic system

The complete system of sewage removal, including the septic field, septic tank and associated piping. There is no connection to a municipality or commercial sewer system.

Septic tank

An underground tank wherein sewage is broken down in an anaerobic bacterial process. Usually composed of two chambers, the septic tank receives the wastewater from the dwelling in the first chamber, which allows the solids to settle to the bottom. The liquid component of the wastewater flows into the second chamber, where further settling takes place. Water then flows into the piping of the septic field, where it is absorbed into the ground and naturally filtered and cleaned.

Service Entrance

A pipe that connects the water company supply to the water meter.


The distance from the top of the well to the top of the pump.


A combination of water carried wastes from a residence, business buildings, institutional and industrial buildings together with ground surface and storm water.

Sewage Ejector Pump

These pumps are required where wastewater cannot flow to its destination by means of gravity at a velocity of at least 2 feet per second. Nearly all residential plumbing systems rely on the force of gravity to move waste through the lines; but, occasionally, a fixture needs to be installed below the nearest available sewer or septic line (for example in a basement bathroom). The waste from the drain for this fixture must be lifted to the level of the main drain.


Drainage outside the building. Note that “drain” is inside the building.

Sewer connection

The place where a dwelling sanitary sewer system connects to the city or municipality sewer system.


Color matched component under a wall-mount lavatory that covers the drain outlet for aesthetic purposes

Shutoff valve

Any piping valve that stops the flow of water in the pipe. Water meter shutoff valves are located underground in a cabinet and use a quarter turn valve rotation. Shutoff valves in the home are usually found under the sink or beside the toilet to shut off water supplied to those fixtures and faucets. They are usually a gate valve that requires several turns to fully close.

Sink basin

The bowl of the sink. Many kitchen sink basins are comprised of two connected basins to allow for washing and rinsing. Bathroom sink basins will include an overflow drain in their design, molded onto the underside of the basin.

Sink plunger

A type of small plunger that fits over a sink drain, used to unstop clogs.

Siphon Break

Recognized by the gurgling sound that takes place at the end of a toilet flush, the siphon break is when air is re-introduced into the trapway, causing the siphoning action to cease.

Siphon-Vortex Water Closet

A type of toilet that has a trapway at the back of the bowl, integral flushing rim, and a water supply system that does not go into the trap.


Suction that takes place when water pressure drops which causes water or waste to be pulled through a descending outlet channel.


A pipe that runs through a wall to allow another pipe through it.

Slip Joint

A connection made with compression fittings.


Satin Nickel

Soil Pipe

Any piping which transports the discharges of one of more water closets or bedpan washers with or without the discharge from other fixtures to the house drain.

Soil Stack

Largest vertical drain line to which all branch waste lines connect; carries waste to the sewer line.

Solar water heater

A water heating system that uses piping that is coiled through heat collectors on the roof. An energy saving device, solar water heaters use the sun for all or part of the water heating process and can be tied into a conventional water heater for backup.


A metal alloy that is melted to join or mend metal surfaces; also, the act of melting solder into the joint.


A common term for a hose bibb.


A spud is a threaded opening on a water heater tank.


An abbreviation normally used for PVC or CPVC fittings, to describe a non-threaded fitting with a spigot end (male) on one side and a slip (female) connector on the other side. The spigot end is the same size as the pipe and glues into a slip fitting. The slip fitting is a normal female hub end that fits over pipe.


A vertical main that reaches multiple stories; the main resides in the drain, waste, and vent system.

Stand Pipe

A stand pipe is the name of several pipe types. A stand pipe is a vertical pipe that receives water from washing machines; a water supply for a fire sprinkler system, or a vertical pipe that has water pumped into it to produce a certain pressure.

Static Lift

In a pump installation, the vertical length of space between the source and discharge water levels.

Static Pressure

The pressure when NO water is flowing.

Stop Valve

A valve that controls the flow of water to an individual fixture, allowing water supply to be stopped to one fixture without affecting the water supply to other fixtures.

Storm water sewer system

A drainage system, separated from the main sewer system, that collects rain and runoff water and transports it to a natural water source. This water contains no sewage and does not need to be treated.

Straight Cross

A straight cross connects four pipes of the same diameter together.

Straight Stop

An “emergency” stop (valve) that is usually installed before the water supply line (below) to toilets and faucets. Angle stops are to be shut off in case of an emergency or repair and are generally not designed for daily on and off usage. The difference between a “straight stop” and an “angle stops” is that the “angle” stop changes direction by 90 degrees while a straight stop is like most valves and does not change direction.

Straight Stop Valve

A shutoff valve, like the angle stop but without the 90 degree turn.

Street Elbow

An elbow (90 degree bend) fitting that has a male end (same size as pipe) on one side and a female end (pipe fits inside this size) on the other side.

Sub-Soil Drain

The part of the drainage system which transports subsoil ground or seepage water to the house drain or house sewer. (Most times it’s called drain tile.)


A pit for draining, collecting, or storing water.

Sump Pump

This type of pump is used where basement flooding happens regularly. A pit is dug in the basement. The water accumulates in the pit. Then, the sump pump pushes the water outside the home and away to an area where it is no longer problematic.

Supply Line

a metal or plastic line that carries water from the Main Line to an individual fixture (e.g. faucet, toilet, etc.) in the home.

Suspended Solids

The solid waste material held afloat or suspended in the transport medium in this case it’s water.


Sweating has two definitions. It is slang for soldering and a term for condensation that builds outside of pipes or toilet tanks.



T & P (temperature and pressure) Valve

A T&P valve is a piece of safety equipment that expels extra pressure or heat from within the tank.


Also known as toilet or closet bolts, T-bolts are 2 anchor bolts that attach a toilet to the floor.

T&P Valves

A relief valve used on tanks or vessels that is activated by too much temperature(T) or too much pressure (P)

Tail Pipe

The tail pipe is added below the jet assembly in a well system.


A section of pipe that is fitted between a fixture outlet and its trap.


A water holding container that reserves a portion of the water supply for future, anticipated use. Toilet tanks hold water for the flush cycle. Water heater tanks reserve heated water for future use.

Tank Ball

The moving part of the flush valve that seals water in or allows water out of the tank during the flush cycle. Also known as the flapper, flush ball, stopper and seal disk.

Tank Bolts

Three bolts that hold together the tank, gasket and bowl of the toilet.

Tank Cover Lock

Device to prevent damage to and removal of the toilet tank cover and contents of the tank.

Tank Cross

A fitting installed between a well pump and a bladder tank with valve, gauge, and an outlet for a pressure-relief valve.

Tankless water heater

A newer style of water heater that does not contain a holding tank. Water is heated on demand after the unit detects water flow. These units are usually heated by natural gas burners.


Tap is synonymous with faucet. Also tap refers to the divergence of water from one fitting to another.

Tap Tee

A tee made of cast iron; this tee has a threaded female inlet.


Any T-shaped plumbing fitting. It has three openings used to create branch lines.

Teflon Tape

Thread sealing tape with stain resistant, water repellant Teflon finish. Teflon is a trademark of DuPont.


A heat treatment technique to strengthen and harden glass for more safety. Also applies to water that has been mixed in order to avoid a temperature extreme.

Tempering Valves

A valve used to control temperature to a constant temperature. These valves are mechanical in nature meaning a temperature can be set with a set and locked in and won’t allow any more hot water through the valve. Hot and cold water flow is controlled by the internal ports.

Thermal Expansion

The expansion of water or material from heat

Thermal shock

A large and rapid change in the water temperature. Thermal shock is a particular concern for showers where rapid changes in the temperature of the water can lead to scalding, as well as increased risk of injuries due to slips and falls. Technologies to prevent thermal shock include pressure-balance and thermostatic shower valves.


small electric generator. Electron flow between the hot junction of 1200ºF and cold junction of 600ºF creates millivoltage.

Thermostatic Mixing Valves

A pressure balanced valve used to control temperature of water based on both the hot and cold water supply temperatures and changes in water pressure. A valve that is pressure balanced only operates on just that….pressure

Thermostatic Valve

Pressure-balancing shower mixing valve with automatic temperature control. When temperature or pressure fluctuations occur at the water inlets, a thermal actuator adjusts the hot and cold ratio to maintain the original temperature setting.

Thread Sealant (LIQUID)

Provides a water seal in threaded connections.

Thread Sealant (TAPE)

Dry ribbons of sealant sold on spools. Unlike liquid sealant there is no chance of it getting into the supply lines and blocking water flow.


Installation where the bath drain tee outlet points down rather than horizontal.

Thumb Nut

To ease installation and to prevent over-tightening this nut was designed to be tightened without tools.

Thumb Screw

To ease installation and to prevent over-tightening this screw was designed to be tightened without tools.


Installation where the sink is fit flush with the countertop

Toilet plunger

A plunger with a flexible end, shaped to be inserted into the drain at the bottom of the bowl. This increases efficiency.

Toilet Setting Compound

Provides a non-hardening watertight seal for the base of the toilet and the floor.


A plumbing fixture designed to receive human excrement from the user of the fixture to the sanitary sewer system.

Torque Wrench

Tool for measuring the amount of force applied to a threaded connection

Touchless faucet

A faucet that does not require the user to turn handles to use. The valve is electrically operated and is controlled by a motion sensor or photo eye.


Threads per inch.

Transfer Valve

Valve the changes the flow of water from one outlet to another


Curved section of drain line that prevents sewer odors from escaping into the atmosphere. All fixtures that have drains must have a “P” trap installed. A toilet is the only plumbing fixture with an “S” trap. The “S” trap is built in to the base of the toilet.

Trap Arm

In a drainage trap, the trap arm acts as a waste arm.

Trap Dip

In a drainage trap, the trap dip is the u-bend.

Trap Primer

A line that connects the cold water line to the drainage trap for the purpose of releasing small amounts of water into the trap to maintain the water seal.

Trap Seal

The seal caused by water in a trap preventing septic gasses from leaking back into the home. The trap seal is measured from the inlet of the trap to the top of the dam.

Trap Weir

The highest point of water held in a trap (either p-trap or s-trap) before it leaves the trap and drains


Channel in a toilet that connects the bowl to the waste outlet. This is where the siphonic action takes place. The trapway is measured in terms of the largest diameter ball which can pass through it. Also called the passageway. A toilet with a wide trapway can help reduce clogs.

Trip Arm

The trip lever on the outside of the toilet tank connects to this

Trip Chain

Chain that connects the toilet trip arm and the flapper on the flush valve

Trip Lever

Flush handle and actuating arm on a toilet tank that is attached to the flapper to make the toilet flush. Also the lever that opens and closes the drain on the bathtub waste and overflow.


Unlike pipes, the measurement of a tube (i.e. 2″) corresponds to it’s outside diameter (OD). So the outside diameter of a 2″ tube is truly 2″.

Two-piece Toilet

The toilet tank is separate from the toilet bowl. This is the most common type of toilet and is also called a close-coupled toilet.




Abbreviation for ultra low flush, which describes a toilet that deliver 1.6gpf or less.


In the plumbing industry, ultra-low flow fixtures and fittings refer to plumbing products that exceed the water efficiency standard of the Energy Policy Act of 1992. The term is used interchangeably with the term “high efficiency”

UNC, UC, or NC

Abbreviation for Unified National Coarse Thread (National Coarse) – Use on fittings, nuts, & bolts – not for pipes.

UNF, UF, or NF

Abbreviation for Unified National Fine Thread (National Fine) – Use on fittings, nuts, & bolts – not for pipes.


A one-piece stop and riser.


Three piece fitting that joins two sections of pipe, but allows them to be disconnected without cutting the pipe. Used primarily with steel pipe; never in a DWV system

Universal design

Universal design should be accessibility that is not apparent and, at the same time, can accommodate a wide variety of people of all ages and statures. It allows access to a richer life by eliminating disability by design. This thoughtful approach to space and barriers allows the maximum number of people to use the widest variety of products in their homes for the greatest length of time.


A plumbing fixture that is flushed by potable water that is designed to receive human urine, the discharge is disposed into the sanitary system.

Usable Storage

The percentage of hot water that can be taken from a tank without lowering the temperature to the point it is not considered hot.



Vacuum Breaker

A device that prevents the backflow of impure water into the water supply system.


A fitting with a movable part that opens or closes one or more passages and thereby allows a liquid flow to be started, stopped, and regulated. In plumbing, valves are used in faucets and showers, and can be called mixing valves because they control the mix of hot and cold water to achieve desired water temperatures.

Valve Seat

A part of the valve that is stationary. Water flow halts when the moveable portion of the valve meets the valve seat.


A bathroom storage cabinet beneath the counter. Some plumbers also call a lavatory sink a vanity. Often a mirror is on the wall above.


The rate of speed at which water moves through piping. It is measured in feet per second.


A pipe that allows air into a drain system to balance the air pressure, preventing water in the traps from being siphoned off.

Vent Header

Several vents connect to the vent header, which leads to the vent stack.

Vent stack

Also called vent pipes. These pipes permit equalization of the pressure in the drain system with the atmospheric pressure. This prevents vacuum conditions that can interfere with the natural flow of the drain piping. The pressure on both sides of drain traps is equalized, assisting in proper flow.

Vent System

A vent system provides an airflow to and from the drainage system. The air protects against siphoning and back-pressure.


For the purpose of creating a suction in a vacuum pump, a venturi is a short, narrow tube that increases the speed of the flow of a fluid and decreases the fluid pressure.


Viscosity is the resistance of fluid flow due to molecular friction.


A surface material on some plumbing fixtures derived from or consisting of glass. It is low in porosity and is translucent. Generally porcelain china is vitreous china.

Vitreous china

A type of pottery most commonly used for plumbing fixtures, such as toilets. It is a compound of ceramic materials fired at a high temperature to form a nonporous body. Exposed surfaces are coated with a ceramic glaze that fuses to the china when fired and gives vitreous china plumbing fixtures their colors and glossy appearance.


Vent through the roof




Water closet – aka: toilet

Wafer Check Valve

A wafer style check valve is obviously a check valve that is used when space constraints won’t allow traditional check valves to be used. Some of the other benefits of using a wafer check is weight, this style of check doesn’t need as much support as it’s traditional full body counterpart. A wafer valve is made using a thin disc that can be fastened in the center or the top or can be spring loaded in the center. This valve is meant to placed between two flanged fittings and secured between the two fittings with all thread rod. The valve is notched in the same positions as the bolt pattern of the flanges so the rod can pass by the valve. The valve is secured at both ends by the flanges.

Washdown Water Closet

A water closet with a front siphon trapway and integral flushing rim.

Washing Machine Box

A fixture on the wall in the laundry area that holds the hot and cold supply lines for the washing machine. It also has a connection to the drain line so that water from the washing machine can be pumped out to the drain.

Waste & Overflow

The drain assembly for a bathtub. The outlet at the top removes the “overflow” water during tub filling and the drain at the bottom removes “waste” water when the tub is drained.

Waste Arm

A waste arm is an extension pipe that extends from a fixture into the wall.

Waste Shoe

Generally refers to a bathtub drain assembly.


Any water that is used in a process or sewer system becomes wastewater or graywater and must be treated before reuse.

Water Closet

Another term for toilet. Many in our industry will write w.c. on drawings or quotes which means water closet (aka: “toilet”).

Water Hammer

Shock waves in plumbing generally due to high velocity water being shut off quickly. This is mainly caused by under sizing of pipes and faucets or valves that are shut off fast. Sometimes installing water hammer arrestors can help alleviate or lessen water hammer. Best is to increase water pipe sizes (thereby slowing velocity).

Water heater

An appliance used to raise the water temperature in a water system.

Water heater gauge

Gauges used to indicate either the temperature or the pressure of water in a water heater, or both.

Water meter

A gauge used to measure the amount of water flow in a system, measured in gallons.

Water pressure

The amount of force, measured in pounds per square inch, that a water system produces.

Water softener

An appliance designed to remove hardness chemicals, such as calcium, from the potable water supply.

Water supply

The potable water supplied to a residence or commercial building.


WaterSense is a partnership program sponsored by United States Environmental Protection Agency, which works to promote water efficiency and enhance the market for water-efficient products, programs, and practices. Similar to the EnergyStar program that helps consumers choose energy-efficient appliances, WaterSense helps consumers to choose water-efficient products by specifying the maximum flow rates and minimum performance levels. Products certified as meeting current WaterSense product specifications are eligible to carry the WaterSense label.

Well pump

A pump used to pull water from an underground natural water supply.

Wet Vent

When the drain discharge of one fixture is put into the vent stack of another fixture. Vertical wet venting is the most common and allows 4 fixtures of one or two fixture units each to discharge (drain) into a vent pipe serving another fixture. This can only be done if all of the fixtures involved are located on the same story as the wet vented fixture.




Not all whites are alike. Euro-white generally is a somewhat yellowish white. Similar to Corian and Avonite’s = Cameo white; Surell/Formica and Wilsonart’s = Frosty white.


Polar-white generally is a bluish white. Similar to Kohler, Elkay, Moenstone, and Swanstone’s = White; Corian’s = Glacier white; Avonite’s = Porcelain white; Surrell/Formica’s = Arctic white.


A style of bathroom lavatory faucet having separate spout and handles. Usually 8″ from center of handle-to-handle. Some widespread faucets can be set with handles up to 12″ apart.


The act of preparing a vacant home for winter by draining out the water heater and water lines and applying products to toilet bowls to prevent them from freezing.


Abbreviation for cold water, oil, gas pressure rating (water oil gas).

Working Pressure

Normal, maximum operating pressure design of a faucet, valve or plumbing product.


A Y-shaped fitting with three openings used to create branch lines.






A casting with hot and cold valves and the mixing chamber for water.

Yoke Vent

A yoke vent prevents pressure changes in the stacks by connecting upward from a soil or waste stack to the vent stack.



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