Why Does My Dishwasher Stink?

September 2025 · Austin Smith

You open the dishwasher expecting clean dishes and get hit with a sour, rotten, or sewer-like smell. The good news: most of the time the cause is simple and you can fix it yourself in 15 minutes. Occasionally it's a drain problem that needs a hand. Here's how to tell which.

The five usual causes

1. A dirty filter

This is the cause nine times out of ten. Most dishwashers made in the last decade have a filter at the bottom of the tub that catches food. It isn't self-cleaning, and when it fills up, that food rots.

2. Mold and mildew on the door seal

A dishwasher is warm and damp, and the rubber gasket around the door rarely dries. A musty smell usually means mildew there or in the corners of the tub.

3. Standing water in the bottom

After a cycle, the bottom of the tub should be nearly dry. Standing water turns stagnant fast. It usually means a clogged filter, a blocked drain, or a failing drain pump.

4. A clogged garbage disposal

In most kitchens the dishwasher drains through the disposal. If the disposal is clogged, or if it's new and the knockout plug was never removed, the dishwasher can't drain properly.

5. A missing drain hose loop

This one surprises people. The dishwasher's drain hose should rise up high under the sink (a "high loop") or run through an air gap on the countertop before it drops to the drain. Without that loop, dirty sink water can flow back into the dishwasher and sit there between cycles. If your dishwasher smells like the sink drain, this is the first thing I check. It's often missed when a dishwasher is replaced.

How to fix it yourself

1. Clean the filter. Twist it out (your manual shows where), rinse it under hot water, and scrub it with an old toothbrush.
2. Clear the spray arms. Use a toothpick to clear any clogged holes.
3. Wipe the door seal with a cloth and white vinegar, paying attention to the bottom edge.
4. Run a vinegar cycle. Put a cup of white vinegar upright on the top rack and run the hottest cycle, empty.
5. Then a baking soda cycle. Sprinkle a cup of baking soda on the bottom and run a short hot cycle.
6. Run the disposal with cold water before starting the dishwasher.

Austin's water is hard, so if you see white, chalky buildup inside the tub, a monthly dishwasher cleaner tablet or vinegar cycle helps with that too.

How to keep it from coming back

• Scrape plates, but don't pre-rinse; modern detergents need some food to work on
• Clean the filter once a month
• Leave the door cracked after a cycle so it can dry
• Don't let dirty dishes sit for days

When to call me

If you've done all of the above and the smell is back within a week, or there's still standing water after a cycle, the problem is in the drain: the hose, the loop, the disposal connection, or the pump. That's work I do regularly. I'll find the cause and fix it, and I'm happy to show you how to clean the filter yourself so you don't need me next time.

Related: Diagnostic visit