Open the door and a stale, sour, or sewer-like smell rolls out. A dishwasher that smells is almost always trapped food or standing water — not a broken machine — and it clears with the right clean-out.
Smell that won’t clear? Call 844-975-6696 or book a visit.
Quick guide
| The smell | Likely cause | Fix it yourself? |
|---|---|---|
| Rotten food smell | Trapped food in the filter | Yes — clean the filter |
| Stagnant, sour water | Not draining fully | Yes — clear the drain |
| Musty or mildew | Biofilm and trapped moisture | Yes — deep clean, air out |
| Sewer or egg smell | Drain hose or air gap | Partly — check the hose loop |
The smell tells you the cause
Match the odor to the source. A rotten-food smell is debris in the filter. A stagnant smell usually means water isn’t draining and is sitting in the bottom. A musty smell is biofilm and moisture in the tub and seals. A sewer or rotten-egg smell points to the drain hose or air gap, not the dishwasher itself.
What causes it
- Trapped food. Debris in the filter and sump rots and smells — the most common cause.
- Standing water. Water that won’t drain goes stagnant fast.
- Biofilm buildup. Grease and residue coat the tub, spray arms, and door gasket.
- Drain hose routing. A hose without a high loop lets sink-drain odors back up into the tub.
- Sitting unused. A dishwasher run rarely, with the door shut, traps moisture and mildew.
If the smell is stagnant water that won’t clear, the underlying issue is drainage — see why it isn’t draining.
Step-by-step: clear the smell
- Clean the filter. Twist it out, rinse it, and clear the sump underneath — start here.
- Check it’s draining. Make sure no water sits in the bottom after a cycle.
- Wipe the gasket and edges. Clean the door seal and tub rim where grime hides.
- Run a hot cleaning cycle. Empty, with dishwasher cleaner or white vinegar, to strip biofilm.
- Check the drain hose loop. A sewer smell often means the hose needs a high loop to block backflow.
- Leave the door ajar. Let the tub dry between cycles to stop mustiness.
When to call a technician
Book a visit soon if a sewer smell persists after cleaning and checking the hose loop, or if the smell is tied to water that won’t drain. Both point to a drain or plumbing issue that’s tested and corrected — a smell that survives a deep clean isn’t just hygiene. Book Thermador dishwasher repair to trace it.
It can wait if a filter clean and a hot cycle cleared it — that’s routine maintenance.
What the repair actually involves
When cleaning doesn’t fix it, a technician checks drainage and the hose routing, clears any blockage, and confirms the drain hose has a proper high loop or air gap to stop sink odors backing up. If a drain component is at fault, it’s cleared or replaced — usually in the least-expensive category, as it’s a hose or connection rather than a major part. You get a written estimate before any work, and the visit focuses on the source, not masking it.
Is it safe to use until then?
Yes — an odor is unpleasant but not unsafe. Standing water is the one thing to deal with promptly, since it grows bacteria and can overflow; clear it and the filter, and the dishwasher is fine to keep using.
Preventing it
- Scrape plates and clean the filter regularly.
- Run a hot cleaning cycle monthly.
- Leave the door ajar to dry, and run the dishwasher at least weekly.
Frequently asked questions
Q: Why does my dishwasher smell like rotten eggs or sewer?
A: That smell usually comes from the drain, not the dishwasher. The drain hose likely needs a high loop to stop sink and sewer odors backing up into the tub. Check the hose routing and the air gap if you have one.
Q: How do I clean a smelly dishwasher?
A: Clean the filter and sump, wipe the door gasket, then run an empty hot cycle with dishwasher cleaner or white vinegar to strip biofilm. Leaving the door ajar to dry between uses keeps the smell from returning.
Q: Why does my dishwasher smell musty?
A: Musty means trapped moisture and biofilm, common if it’s run rarely with the door shut. A hot cleaning cycle, a wiped gasket, and airing it out between uses clears it and keeps it away.
Q: Can standing water cause the smell?
A: Yes — water that won’t drain goes stagnant within a day and smells sour. Clear the filter, hose, and drain so it empties fully; if it keeps leaving standing water, the drainage needs fixing.
Freshen it up for good
If a deep clean doesn’t clear a drain-related smell, we’ll trace the cause. We handle Thermador dishwasher repair with a written estimate before any work starts.
Call 844-975-6696 or book online. Same-day service is usually available in New York, Los Angeles, Chicago, San Francisco, Houston, and Miami.