Note to readers: This post was updated on July 10, 2026 to reflect current best practices for storm-season flooding prevention and add links to our related drain and sewer inspection guides. We refreshed the details below so the advice reflects how we approach this work today.
Southern California doesn’t get much rain, but when it comes, it comes fast — and a lot of homes aren’t ready for it. Storm drains back up, yards flood, and water finds its way into garages and low-lying rooms before anyone notices there’s a problem. If you’ve ever had water creeping toward your door during a downpour, you already know how stressful it is.
Why Rain Causes Flooding Even in a Dry Climate
Most homes in the San Gabriel Valley were built for infrequent rain, not sustained storms. That means a few common issues show up every rainy season:
- Overwhelmed yard drains — leaves, dirt, and debris clog area drains right when you need them most.
- Sewer backups — heavy rain can overload the municipal sewer system, pushing water back up through your home’s lowest drains.
- Grading and slope problems — older homes sometimes have grading that channels water toward the house instead of away from it.
- Clogged or undersized drain lines — a line that’s been slowly narrowing for years finally can’t keep up once real volume hits it.
Signs You’re About to Have a Flooding Problem
Flooding rarely happens without warning. Watch for:
- Water pooling in the yard that doesn’t drain within a few hours
- Gurgling sounds from drains during or after rain
- Water backing up into a tub, shower, or floor drain
- Damp spots along the base of exterior walls
If you notice any of these during a storm, don’t wait it out — emergency flood and drain service is worth calling before water gets into the house.
What to Do When Water Starts Coming In
If flooding is already happening, act quickly:
- Move anything valuable off the floor and away from the affected area
- Shut off electrical circuits to flooded rooms if it’s safe to do so
- Avoid running any water inside the house if you suspect a sewer backup — that only adds volume to the problem
- Call a plumber who can pump water out and diagnose the cause the same day
How a Sewer Video Camera Helps
Once the water is under control, the real question is why it happened. A sewer video camera inspection lets a technician see exactly what’s going on inside your main line — root intrusion, a bellied pipe, buildup, or a break — without digging up your yard to find out. It’s the fastest way to know whether the fix is a simple cleaning or something more involved.
Preventing It Next Time
A few habits go a long way toward staying dry the next time a storm rolls through:
- Clear yard and area drains before the rainy season starts
- Have your main line cleaned if it’s been more than a year or two — our guide on main line drain cleaning covers what that involves
- Watch for clogged rain drain pipes, which are one of the most common causes of yard flooding
- If backups are recurring, ask about the facts and myths around sewer backups so you know what’s actually normal and what isn’t
Western Rooter runs 24/7 emergency service for exactly this situation. If a storm has water heading toward your home, call 626.448.6455 — we bring the pumps and the equipment to get ahead of it.
