2026-03-111 min read

Dishwasher smells like sewage: causes and fixes

A sewer smell from your dishwasher is usually trapped gunk, a dry trap, or a drain/venting issue. Here’s what to check first.

A sewer smell almost always comes from the drain path, not the wash cycle.

1) Clean the filter and the bottom basin

Pull the filter and scrub any slime or food buildup.

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2) Check the drain hose for backflow

If the hose isn’t installed with a high loop (or air gap), sink water can flow back.

3) Run the garbage disposal (if connected)

Old disposal buildup can stink and push odor back into the dishwasher.

4) Verify the sink P-trap has water

If a drain trap dries out (rare in kitchens, common in unused drains), sewer gas can come up.

5) Run a hot cycle with an empty load

After cleaning, run the hottest cycle to flush the system.

When to call a plumber

If odor returns quickly and the sink drains poorly, you may have a venting or drain-line issue.

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