Dishwasher smells can come from food scraps, a dirty filter, mildew, or dirty water that is not draining properly. Start by checking those areas rather than adding cleaning products indiscriminately. The right cleaner depends on your appliance and the type of buildup.
What causes dishwasher odors?
- Food residue: Particles trapped in the tub bottom, filter, or pump inlet can remain in the machine and cause odors.
- Mildew: It can grow inside the dishwasher or on the door gasket, especially when food residue is present and the machine is used infrequently.
- Detergent buildup: Whirlpool recommends routine interior cleaning to remove this residue and reduce odors.
- Drainage problems: According to GE, dirty water standing in the tub between uses can signal an installation or drainage problem.
If a new Whirlpool dishwasher smells like plastic, Whirlpool says this new-appliance odor is normal and should dissipate in about two weeks. That is different from a persistent smell associated with residue or standing dirty water.
How to check and clean a smelly dishwasher
Check your model’s manual before removing the filter or choosing a cleaner. Only remove the filter if your manual provides instructions for doing so. The cleaning-product directions below are manufacturer-specific, not universal instructions for every dishwasher.
- Remove visible debris. Check the tub bottom and pump inlet screen. GE recommends clearing food particles, paper, or plastic that is blocking the inlet.
- Clean the removable filter. Whirlpool instructs owners to remove the filter assembly and rinse it under running water. Use a soft brush to loosen stubborn soil or calcium deposits until the mesh is free of visible buildup. Reinstall it according to the manual.
- Check the spray arms. GE recommends inspecting the jet openings and gently clearing blockages with a small object, such as a paper clip.
- Run the cleaning cycle appropriate for your appliance. To flush out residual food, GE recommends running the dishwasher without dishes, using dishwasher detergent. Follow the cleaning directions for your model rather than treating a daily-wash detergent dose as a cleaning-cycle dose.
- Treat mildew only with a compatible product. For appliances covered by its instructions, GE recommends wiping the interior or door gasket with a cloth and a solution of 1/2 cup chlorine bleach per gallon of water. Check compatibility in your manual first: affresh advises against bleach in stainless-steel dishwashers because it can damage and discolor stainless-steel finishes. Do not combine this treatment with other cleaners.
- Rinse after treating mildew. GE recommends running a rinse cycle to clear the cleaning solution before loading dishes again.
Which cleaning products do manufacturers recommend?
Whirlpool: a dedicated cleaner for routine maintenance
Whirlpool recommends affresh Dishwasher Cleaner every 30 days to reduce odors and remove detergent buildup. For cleaning without dishes, the product directions call for one tablet in the detergent tray and a normal wash cycle. For significant buildup, they call for a second tablet in the bottom of the tub. Follow both the appliance and product instructions, without adding bleach.
Bosch: cleaners and descalers do different jobs
Bosch recommends using its dishwasher cleaner a few times a year to remove grease, starch, and protein residue. It separately recommends its descaler a few times a year for hard-water deposits. Dosing depends on the model, so follow your specific owner’s manual. For stainless-steel exterior surfaces, Bosch warns against abrasive and chlorine-based cleaners.
Vinegar: not the default maintenance cleaner
Whirlpool favors a dedicated cleaner for monthly maintenance. Although it also publishes a vinegar-rinse procedure, it warns that vinegar is acidic and can damage the dishwasher if used too often. Do not turn vinegar into a continuous-use additive.
What never to mix
Never mix chlorine bleach with ammonia, vinegar, citric acid, or other cleaning products. CDC guidance says never to combine bleach or disinfectants with other cleaners or disinfectants because the mixture can release dangerous vapors. GE specifically warns that bleach and ammonia produce toxic fumes when combined.
The affresh Dishwasher Cleaner label also warns that mixing it with other products creates dangerous fumes and explicitly prohibits mixing it with liquid bleach. The treatments described here are separate routines—not products to combine in one cycle.
How to keep the smell from returning
- Scrape off large food scraps before loading. Whirlpool recommends scraping rather than pre-rinsing dishes.
- Use a rinse cycle while waiting for a full load. Whirlpool recommends running “Rinse and Hold” or “Rinse Only” every 24 hours without detergent when a full load is not ready.
- Avoid long stretches without use. GE says running the dishwasher at least once a week can usually prevent mildew growth.
- Match detergent dosing to your manual. The amount depends on water hardness and, in KitchenAid’s instructions, the soil level and detergent type. More detergent is not a substitute for cleaning: KitchenAid warns that excess detergent in soft water can etch glassware.
When cleaning is not enough
If dirty water remains in the tub between uses, have the drainage and installation checked rather than repeatedly adding more cleaning products. GE identifies possible causes including a drain hose without a high loop, an improper connection to an air gap, or a blocked drain in a connected garbage disposal.
Where installed, the air gap is the chrome-plated cylinder on the sink deck that prevents backed-up drain water from siphoning into the dishwasher. It is part of the plumbing, not the appliance.
GE considers odors that remain for extended periods abnormal. If the smell persists after the appropriate cleaning routine, or dirty water keeps returning, request service to assess the dishwasher and its installation.