Dishwasher smells usually come from food, grease, or standing water trapped where the wash water does not fully clear it. The filter, sump, drain hose, disposal connection, air gap, and gasket are the common spots.
These steps apply to standard built-in dishwashers from Bosch, Whirlpool, GE, Samsung, LG, KitchenAid, Frigidaire, Maytag, and similar brands.
Does this affect you?
A musty odor points to trapped moisture or mildew around the gasket and tub. Rotten-egg or sewage smells often point to the drain connection, garbage disposal, air gap, or household drain path.
Clean the filter
A dirty filter is the most common dishwasher odor source.
- Pull out the lower rack.
- Find the round twist-lock filter in the tub floor.
- Twist counterclockwise and lift it out.
- Rinse under hot water and scrub the mesh with an old toothbrush.
- Wipe out the sump well where the filter sits.
- Lock the filter back in and run an empty cycle.
Check the drain connection
- If the dishwasher drains through the garbage disposal, run the disposal with cold water for 10 to 15 seconds.
- If a disposal was recently installed, make sure the dishwasher knockout plug was removed.
- If you have an air gap on the counter, remove the cap and clear buildup.
- Check the drain hose for a sagging low spot where water can stagnate.
Run a cleaning cycle
- Run the dishwasher empty.
- Place a dishwasher-safe cup of white vinegar on the top rack or use a dishwasher cleaner tablet.
- Use the hottest cycle available.
- Afterward, wipe the rubber gasket by hand.
- Leave the door cracked between loads so the tub can dry.
A cracked or brittle gasket can trap moisture and grow mildew even after the tub is clean. Greasy pans and starch-heavy dishes also build residue in the filter and drain line faster, so lightly scraping or rinsing the worst items helps.
If a strong sewage smell remains after the filter, disposal, air gap, hose, and gasket are clean, the issue may be farther down the drain line or a dry P-trap. That is worth a plumber’s look.
Sources
- Whirlpool – Why Does My Dishwasher Smell? (2025)
- GE Appliances – Dishwasher Odor Troubleshooting (2025)
- Bosch Home – Removing Bad Smells from a Dishwasher (2024)