Quick answer
A mildewy smell in your dishwasher is often caused by trapped moisture and food particles. Clean the filter, rinse aid dispenser, and door seal, and run a vinegar cycle to eliminate the odor.
Confirm the symptom
- Smell is musty or like mildew
- Smell comes from the dishwasher itself
- Smell worsens after a wash cycle
- Smell is not from the garbage disposal or sink
Tools and prep
- Rubber gloves
- White vinegar or dishwasher cleaner
- Baking soda
- Soft brush or toothbrush
- Microfiber cloth
- Empty dishwasher
- Turn off power to dishwasher (via circuit breaker)
Step-by-step troubleshooting
- Clean the FilterDo: Remove the filter at the bottom of the dishwasher and rinse it under warm water. Use a soft brush to scrub away debris.Observe: Filter is clogged with food particles and grime.Means: Clogged filter is trapping moisture and causing mildew.Next: Clean the filter thoroughly and reinstall it.
- Clean the Door SealDo: Wipe the rubber door gasket with a damp cloth and baking soda paste. Scrub any visible mold or mildew.Observe: Door seal has mold or mildew buildup.Means: Moisture trapped in the seal is causing the smell.Next: Dry the seal completely after cleaning.
- Clean the Rinsing Aid DispenserDo: Remove the rinse aid dispenser and clean it with warm, soapy water. Wipe the reservoir with a cloth soaked in vinegar.Observe: Dispenser has residue or mildew inside.Means: Old rinse aid or water is causing the odor.Next: Reinstall the dispenser after cleaning.
- Run a Vinegar CycleDo: Place a cup of white vinegar in a dishwasher-safe container on the top rack. Run a hot water cycle without dishes.Observe: Smell dissipates after the cycle completes.Means: Vinegar neutralizes mildew and odors.Next: Dry the dishwasher thoroughly after the cycle.
- Check for Standing WaterDo: Inspect the bottom of the dishwasher for any standing water after the cycle ends.Observe: Water remains at the bottom of the dishwasher.Means: Poor drainage is allowing mildew to grow.Next: Check the drain hose and pump for clogs if water remains.
- Dry the InteriorDo: After cleaning, leave the dishwasher door slightly open to allow air circulation and drying.Observe: Interior remains dry after a few hours.Means: Proper ventilation prevents future mildew.Next: Monitor for return of the smell over the next few days.
Common causes
| Cause | Likelihood | Difficulty | Part often needed |
|---|---|---|---|
| Clogged Filter Trapped food particles and moisture create a breeding ground for mildew. | Common | Easy | Dishwasher Filter |
| Dirty Door Seal Mold and mildew grow in the rubber gasket if it's not cleaned regularly. | Common | Easy | Door Seal Cleaner |
| Rinse Aid Residue Old or expired rinse aid can leave a film that promotes mildew growth. | Sometimes | Easy | Rinse Aid Dispenser |
| Standing Water Poor drainage allows water to sit and develop mildew. | Sometimes | Medium | Drain Pump |
| Lack of Ventilation A closed door after a cycle traps moisture inside the dishwasher. | Sometimes | Easy | Ventilation Solution |
| Hard Water Deposits Mineral buildup can trap moisture and create a mildewy smell. | Rare | Medium | Water Softener |
Parts matching
Common parts needed to address a mildewy smell in your dishwasher include:
- Dishwasher Filter
- Door Seal Cleaner
- Rinse Aid Dispenser
- Drain Pump
- Ventilation Solution
- Water Softener
Purchase replacement parts compatible with your dishwasher model for best results.
When to call a professional
- Smell persists after multiple cleaning attempts
- Standing water remains despite cleaning the drain hose and pump
- Dishwasher makes unusual noises during the drain cycle
- You notice visible mold growth inside the dishwasher
- You suspect a broken drain pump or internal component
FAQ
How often should I clean my dishwasher filter?
Clean the filter at least once every 1–2 months to prevent clogs and mildew buildup.
Can I use bleach to clean my dishwasher?
Avoid using bleach, as it can damage rubber seals and leave harmful residues. Use vinegar or a dishwasher-specific cleaner instead.
Why does my dishwasher smell even after cleaning?
Persistent odors may indicate a deeper issue like a clogged drain pump or poor ventilation. Check for standing water or consider calling a professional.
Is it normal for my dishwasher to have a slight smell after a cycle?
A slight damp smell is normal, but a strong mildewy odor indicates a problem that needs attention.
Can hard water cause a mildewy smell?
Yes, hard water can leave mineral deposits that trap moisture and promote mildew growth. Consider using a water softener if this is a recurring issue.