Dishwasher smells bad
A dishwasher that smells bad usually has food or dirty water trapped somewhere inside it.
Not urgent A food or musty smell is a cleaning job first; a burning or electrical smell is different, and means switching the dishwasher off at the breaker.
What this symptom usually means
A dishwasher that smells bad usually has food or dirty water trapped somewhere inside it. Whirlpool names food debris caught in the filter, the spray arms or the bottom of the tub, and water left standing because of a drain problem or a blocked filter. Bosch says food particles collect in the filter with every wash. Bosch's UK site adds that waste water isn't pumped away properly when the filter is blocked or the drain hose is kinked. GE says dirty water building up between uses may be an installation problem: the drain hose needs a high loop under the counter, or an air gap, so water from the sink or disposer can't run back into the dishwasher. A musty, mildew smell is more common in a dishwasher that sits unused. GE says running it at least once a week usually prevents mildew, which matters in a cottage kitchen or while you're away for a few weeks.
Some smells are normal in a new dishwasher. Whirlpool says a plastic smell usually fades within about two weeks, a petroleum smell from the sound-deadening material within four to six weeks, and a varnish smell from the motor coating within about a month. A burning or electrical smell is not in that category, and neither is a sewage smell that comes with water backing up into the sink.
Checks you can do yourself
- Clean the filterTake out the filter at the bottom of the tub as your manual shows and rinse it under hot water. Bosch suggests soap and a soft brush. Whirlpool says to do this at least once a month.
- Clear the spray armsCheck the spray-arm holes for seeds, glass or labels. GE suggests a paper clip and Bosch a toothpick to clear blocked holes.
- Wipe the door seal and tub edgesWhirlpool says to wipe the door seals with a damp cloth and mild detergent. Include the bottom edge of the door and the corners of the tub, where food gets trapped.
- Run a cleaning cycleRun the dishwasher empty on a hot cycle with a dishwasher cleaner, or white vinegar, as Whirlpool suggests. GE also suggests a cycle with a full detergent cup and no dishes.
- Treat mildewGE's method is about 4 litres (1 gallon) of water mixed with 125 mL (½ cup) of chlorine bleach or ammonia, never both together, used to wipe the interior and gasket, then a rinse cycle before loading dishes. Check your manual first for anything it says not to use on your tub.
- Check the drain sideIf the dishwasher shares a drain with a disposer, run the disposer before starting the dishwasher, as Whirlpool suggests. Look under the sink for a kinked drain hose, which Bosch lists, and note whether the hose loops up high under the counter.
- Use it regularlyGE says running the dishwasher at least once a week usually prevents mildew. Before a long trip or when closing a cottage, clean the filter, run a cycle, and leave the door slightly open.
Nothing above involves gas, wiring, refrigerant or removing panels.
What you notice, and what it can point to
Listed in no particular order. They help you describe the problem; only an inspection confirms the fault.
Sour food smell, filter not cleaned in months
Could point to: Debris trapped in the filter
Next step: Clean the filter and run a hot cleaning cycle
Musty smell after the dishwasher sat unused
Could point to: Mildew in the tub or gasket
Next step: Clean the gasket; run it at least weekly, as GE suggests
Dirty water in the bottom between uses
Could point to: Drain hose without a high loop or air gap, or a blocked filter
Next step: Clean the filter; check the hose; book if water returns
Sewage smell when the sink drains
Could point to: Back-siphoning from the sink or disposer, or a household drain problem
Next step: Run the disposer first; book or call a plumber
Plastic or petroleum smell from a new dishwasher
Could point to: New materials, normal for a few weeks
Next step: Whirlpool says it fades in two to six weeks
Burning or electrical smell
Could point to: Motor, heater or wiring fault
Next step: Switch off at the breaker and book a technician
How it differs by design
- Manual-clean filters: most current dishwashers from Whirlpool, Bosch and others have a removable filter at the bottom of the tub. Whirlpool says to clean it at least once a month; skip it, and it's the most likely source of the smell.
- Drain connection: GE says the drain hose must be installed with a high loop or through an air gap. Without one, sink or disposer water can siphon back and sit in the tub. The connection under the sink is part of the installation; see dishwasher installation.
- Cleaning products differ by brand: Whirlpool uses a dishwasher cleaner or white vinegar; Bosch suggests its own cleaner several times a year on the hottest, longest cycle, and a descaler where there's limescale. Bosch's UK site suggests a maintenance wash every four to six months.
What our technician checks
These need panels off, live electrical tests or a licensed trade, so they are left to the technician:
- Removing the kick plate, sump or drain pump
- Disconnecting the drain hose from the disposer or air gap
- Clearing a blocked household drain (a plumber)
- Any work near the wiring box under the dishwasher
Waived when you go ahead with the repair. You get the cause, the price and our repair-or-replace verdict in writing before any work.
Repairs a technician may recommend
After inspection, not from the symptom alone.
Drain hose re-routing or air gap installation
When water siphons back from the sink or disposer because there is no high loop or air gap, which GE says causes dirty water to build up between uses.
Drain pump or check valve repair
When water stays in the sump after the cycle with a clean filter and straight hose. See dishwasher not draining.
Sump and filter housing cleaning
When debris has collected below the removable filter, where an owner can't reach.
Door gasket replacement
When the tub gasket is torn or so stained that it keeps smelling after cleaning.
Referral to a plumber
When the smell comes from a blocked household drain or trap rather than the dishwasher.
Brands we see with this problem
Codes, parts and access differ by brand; the brand pages cover where the model label is and what to expect.
Cost, and whether to fix it
What the repair costs depends on the part, the labour and whether a second visit is needed for an ordered part; the written finding gives the total before any work. Our guides on what drives repair costs, dishwasher repair costs and repair versus replacement explain how to weigh it.
When to book
Book if the smell comes back within a few days of cleaning the filter, spray arms and seals and running a cleaning cycle, or if water stays in the bottom after cycles. Tell us whether the dishwasher shares a drain with a disposer and whether the smell is food, musty or sewage-like. The visit is $89 with a written finding, waived if you go ahead with the repair. Dishwasher repair explains what the diagnosis covers.
We handle this across Ottawa and Gatineau
Related problems
Dishwasher smells bad: questions
Why does my dishwasher smell like rotten eggs or sewage?
The usual cause is food trapped in the filter, or dirty water from the sink or disposer getting back into the dishwasher. GE says the drain hose needs a high loop or an air gap to stop that. If the smell comes with water backing up into the sink, a plumber may be needed.
How do I get rid of the smell in my dishwasher?
Clean the filter and spray arms, wipe the door seals, and run an empty hot cycle with a dishwasher cleaner or white vinegar, which Whirlpool suggests. Repeat monthly.
How often should I clean my dishwasher filter?
Whirlpool says at least once a month. More often if you don't pre-scrape plates or you wash a lot of heavily soiled pots.
Why does my new dishwasher smell like plastic?
Whirlpool says a plastic smell is normal and usually fades within about two weeks, and a petroleum smell from sound-deadening material within four to six weeks. A burning smell is not normal.
Can I use bleach to clean my dishwasher?
GE describes a bleach solution for mildew: about 125 mL (½ cup) of chlorine bleach in 4 litres (1 gallon) of water, never mixed with ammonia, followed by a rinse cycle. Check your manual first, since some manufacturers limit what can be used on their tubs.
Sources
- Whirlpool Product Help: Removing odors in your dishwasher
- GE Appliances: Dishwasher - food or mildew odor
- Bosch US: How to clean a smelly dishwasher
- Bosch UK: Dishwasher smells bad
Sources checked 2026-09-24.
Book the diagnostic
Tell us this symptom and your postal code; it helps us bring the right parts.
Online booking is a request. We confirm the appointment by text or phone within 1 business hour.
- $89 diagnosticWaived when you go ahead with the repair
- Written finding on every visitCause, price and our repair-or-replace verdict
- 90-day warrantyOn labour and the parts we install