Note to readers: This post was updated on July 26, 2026 to clarify the most likely causes in order of probability and add links to related drain and sewer guides. We refreshed the details below so the advice reflects how we approach this work today.
A sewage smell coming from your dishwasher is unpleasant, but it’s also useful information — it usually means one of a few specific things is going on. Here’s how to track down the cause and get your dishwasher smelling normal again.
What Causes a Dishwasher to Smell Like Sewage?
1. A dirty or clogged filter
Most dishwashers have a filter at the bottom that traps food particles. When it’s not cleaned regularly, trapped food can rot and produce a smell similar to sewage. This is by far the most common cause and the easiest to fix.
How to fix it:
- Remove the drain filter (check your owner’s manual for its exact location — it’s usually at the bottom of the tub)
- Rinse it thoroughly in the sink with warm water and dish soap
- Check the drain area underneath for any leftover debris or buildup
- Reinsert the filter and run an empty cycle to confirm the smell is gone
2. A blockage in the dishwasher drain line
Dishwasher drain lines connect into your kitchen’s plumbing system, and debris can sometimes work its way in and cause a partial blockage. If cleaning the filter doesn’t resolve the smell, this is the next likely culprit, and it’s worth having a plumber inspect the line rather than guessing.
3. A problem with your main sewer line
This is less common but more serious. If your main sewer line is backing up, dishwashers and other low-lying fixtures can be the first place the smell shows up, since they sit close to the drain path. If you notice the smell alongside gurgling drains elsewhere in the house, slow drains in multiple fixtures, or sewage odor near floor drains, shut off water use in the house and call a plumber right away — see our guide on warning signs you need a drain cleaning for more context on what to watch for.
Preventing the Smell From Coming Back
Clean the filter every one to two months, scrape food off dishes before loading, and run an empty maintenance cycle with a dishwasher cleaner occasionally. If you want a natural option, baking soda and vinegar work on dishwasher drains too, not just bathroom ones.
Still Smells Bad?
If you’ve cleaned the filter and the smell persists, it’s time to call a professional. Western Rooter & Plumbing can inspect your dishwasher’s drain line and, if needed, check the main line for a bigger issue. Give us a call to get it sorted out before it turns into a bigger repair.
