Dishwasher smells bad

A smelly dishwasher is unpleasant, but it's rarely a broken machine — most of the time it's trapped food or a gunky seal, and a good clean fixes it in an afternoon.

tuneWhat are you noticing?

Select anything that matches and the checklist below reorders to fit. Not sure? Skip it.

emergency_home

flag

Start here

In Canadian kitchens, check the filter first — it's the culprit far more often than anything else. Twist out the cylindrical filter in the tub floor and look at the food trap beneath it; if it's packed with wet debris, that's the most likely source to rule out. Rinsing it clean and running a hot cleaner cycle usually fixes the problem outright.

Ranked from real-world failure data. The order updates as you select what you’re noticing above.

Likely causes, in the order to check them

Showing the typical order

Beginner-friendly Doable, with care Safety-critical Call a pro

visibilityHow to check

Pull out the bottom rack to expose the tub floor. The filter is usually a cylindrical piece in the centre or back corner that twists a quarter-turn to release.
Lift the filter out and look at it and the flat mesh trap beneath it — trapped food, grease, and a foul smell when you get close confirm this is the source.
Check while you're there for anything lodged in the trap — glass chips, seeds, labels off jars — that a rinse alone won't clear.

buildNo tools schedule5 min

handymanHow to fix it

Twist out and rinse the filter and food trap under hot water, scrub the mesh with an old toothbrush, wipe out any sludge from the sump, refit the filter, and run an empty hot cycle with a dishwasher cleaner to clear what's left.

Remove the bottom rack, twist the filter a quarter-turn to unlock it, and lift it out along with the flat mesh trap if it lifts separately.
Rinse both under hot running water and scrub the mesh and pleats with an old toothbrush until the water runs clear. Wipe any sludge out of the sump opening with a paper towel.
Refit the filter, twisting it until it locks — a loose filter lets food past and back into the pump.
Run an empty cycle on the hottest setting with a dishwasher cleaner (or a cup of white vinegar on the top rack) to flush the tub.

schedule20 min savings$5–15

Dishwasher cleanerAny CSA/Health-Canada-listed dishwasher cleaner (e.g. Affresh, Finish) sold at Canadian grocers and hardware stores; white vinegar works as a cheap substitute

gavel Check your province first AB: homeowner may do this · BC: homeowner may do this · ON: homeowner may do this · PE: homeowner may do this · QC: homeowner may do this
Cleaning the filter, gasket, and tub is routine homeowner maintenance in every province.

handymanHow to fix it

Wipe the door gasket and its folds with a cloth and a mild cleaner, clear the spray-arm holes, then run an empty hot cycle with a dishwasher cleaner or white vinegar to break down the grease and biofilm.

Pull back the rubber door gasket and wipe the folds, the door edges, and the lip under the door with a damp cloth and a little dish soap or a mild cleaner — this is where slime hides.
Check the spray-arm holes for clogs and poke any blocked ones clear with a toothpick so the arms rinse the tub properly.
Run an empty cycle on the hottest setting with a dishwasher cleaner, or a cup of white vinegar placed upright on the top rack, to cut the remaining grease and biofilm.

schedule20 min savings$5–15

Dishwasher cleanerAny CSA/Health-Canada-listed dishwasher cleaner (e.g. Affresh, Finish) sold at Canadian grocers and hardware stores; white vinegar works as a cheap substitute

visibilityHow to check

Open the cabinet under the kitchen sink and find the corrugated dishwasher drain hose where it connects to the sink drain or garburator.
Trace the hose: it should rise up and be fastened high — near the underside of the countertop — forming a high loop before it drops to the drain connection, or it should run through an air gap on the sink deck.
If the hose runs flat or dips low the whole way with no high point, drain water and smell can siphon back toward the dishwasher. That routing is the likely cause.

buildflashlight schedule10 min

handymanHow to fix it

Fasten the drain hose up under the countertop so it forms a high loop before dropping to the sink-drain connection (or confirm the air gap is used), which stops sink-drain water and smell from siphoning back into the dishwasher.

Under the sink, gently lift the corrugated drain hose so it rises to just under the countertop before dropping to the drain fitting.
Fasten it at that high point with a hose clip or zip tie screwed into the cabinet wall, holding the loop in place so it can't sag back down.
If your setup has an air gap on the sink deck, make sure the hose feeds through it correctly instead — the air gap does the same job as the high loop.
Run a cycle and confirm it drains cleanly with no smell backing up. If the drain connection itself needs changing, stop and call a plumber — see the gate.

schedule30 min savings$5–20

warning Reroute the hose — but leave the drain plumbing to a proLifting and clipping the drain hose into a high loop is a fine homeowner job. But if the fix means changing the actual drain connection, adding an air gap, or reworking pipe under the sink, that's plumbing work — and in some provinces drain modifications are restricted to a licensed plumber. If the routing can't be fixed by repositioning the existing hose, that's the point to call one.

gavel Check your province first AB: homeowner may do this · BC: permit + inspection required · ON: homeowner may do this · PE: homeowner may do this · QC: permit + inspection required
Repositioning the existing drain hose is generally permitted homeowner work; changing the drain connection itself may route to a licensed plumber depending on the municipality.

sort

Why the list is in this order

We don’t sort by likelihood alone. We sort the way a good, honest tradesperson thinks: rule out the free, safe, common causes first. That’s why the cheap checks outrank the expensive repairs — and why anything dangerous gets a hard stop instead of a pep talk. The order exists to save you money, not to sell you anything.