How to Clean a Dishwasher That Smells

A dishwasher that smells is not dirty in a general way — it is holding food in one of five specific places, and you can usually find which one in under ten minutes. In order of likelihood: the filter assembly in the floor of the tub, the spray arm jets, the rim and gasket around the door, the sump under the filter, and the drain line. Almost everything written about this problem tells you to run a cycle with a cup of vinegar on the top rack. That will deodorise the air inside the machine for a day or two and remove none of the food.

The procedure below clears all five, in the order that stops you doing the same work twice — you take the filter out first so that everything you dislodge afterwards has somewhere to fall, and you run the cleaning cycle last so it flushes the lot. Budget about 40 minutes of hands-on work plus one long empty cycle. Two of the steps involve chemicals that can permanently damage a stainless steel tub or perish the door seal, so read the warnings where they appear rather than skipping ahead.

Why dishwashers smell: the five causes, ranked

• A clogged filter. On any dishwasher made in roughly the last fifteen years, food scraped off your plates ends up in a removable filter in the floor of the tub. It is designed to be emptied by you. If nobody has ever emptied it, that is your smell and nothing else you do will fix it.
• Blocked spray arm jets. Seeds, rice grains, bits of label and hard water scale plug the small holes. That both wrecks cleaning performance and leaves food sitting inside the arm itself.
• The door edge and gasket. The strip of tub below the door, and the rubber seal around it, sit outside the wash path. Water and food get there; the spray never does.
• A drain fault. If there is standing water in the sump after a finished cycle, the machine is not draining, and no amount of cleaning will help until that is fixed. This is the cause that gets misdiagnosed most often.
• Not running it enough. A dishwasher used once a week sits damp with a few days of food in it between runs. That is a mildew smell rather than a rotting one — different smell, different fix.

First, find out whether your dishwasher has a filter you clean

Open the door, pull the bottom rack out, and look at the floor of the tub, usually beneath or just behind the lower spray arm. You will see one of two things.

A manual filter (most dishwashers today)

Typically two parts: a cylindrical fine filter that twists out counter-clockwise, sitting inside a flat coarse filter or mesh plate that then lifts free. On Miele machines there is a third element — a micro filter that pulls downward off the assembly by its plastic ring, and which is the part people leave dirty because they never realise it separates. Manufacturer intervals range from “after every use” to “every few months”; the brand-by-brand figures are further down this page.

A hard food disposer (older machines and some current US models)

A fixed grinder assembly with no part that twists out. These are self-cleaning by design. If nothing rotates or lifts with light hand pressure, stop — do not lever it. Check your model number in the manual before touching it. Forcing a fixed filter assembly is how people crack the sump housing, and a cracked sump leaks under the cabinet where you won’t see it for weeks.

What you need before you start

• Washing-up gloves — non-negotiable, see the warning below
• An old toothbrush and, ideally, a narrow detail brush
• Wooden toothpicks for the spray jets — not a paper clip, not wire, for the reason set out in the spray-arm section
• Two microfibre cloths
• A bowl of hot water with washing-up liquid in it
• A dishwasher cleaner or descaler approved for your machine — not a general-purpose bathroom product

The brushes are what make this quick. A worn toothbrush will not reach into a spray arm or along a gasket channel, and you end up doing three passes where one would have done. If you want the small stiff detail brushes that make this kind of job fast, they’re in what a professional cleaning caddy actually holds — it’s the same handful of tools for the dishwasher, the oven and the shower door.

The full procedure

About 40 minutes of hands-on work, then a cleaning cycle that will run somewhere between 1.5 and 2.5 hours on most machines. Do it in this order.

1. Empty the machine completely and pull out both racks (2 minutes). The lower rack usually rolls right off its rails. Working with the racks in place is why this job takes people an hour.
2. Remove the filter assembly (3 minutes). Twist the cylindrical filter counter-clockwise and lift it out, then lift out the flat coarse filter underneath. Take a photo on your phone first if you are unsure how they seat together — refitting them wrongly lets food straight into the pump.
3. Soak and scrub the filters (10 minutes, mostly unattended). Drop them in the bowl of hot soapy water. Leave them while you do the next steps, then brush both sides of the mesh under running water. Hold the fine filter up to a light — if you can’t see light through the mesh, keep going. Do not use a wire brush or an abrasive pad; scoring the mesh makes it clog faster.
4. Clear the sump and the pump inlet (5 minutes). With the filters out you can see down into the sump. Gloved, lift out anything solid. Wipe the surrounding floor of the tub with a cloth. If there is standing water down there that will not drain, stop and read the drain section below — cleaning will not fix it.
5. Do the spray arms (10–15 minutes). Full method in the next section. Do this with the filters still out so the debris drops where you can retrieve it.
6. Clean the door edge, the gasket and the detergent dispenser (8 minutes). Pull the door fully down and wipe the strip of tub below the door opening — the part that stays dry during a cycle. Run a damp cloth around the rubber gasket, then go along it again with the detail brush in the channel where it meets the tub. Open the detergent dispenser flap and brush out the caked residue in its corners.
7. Refit the filters, then the racks (3 minutes). The coarse filter goes back first, then the cylindrical filter twists clockwise until it locks. Give it a gentle tug — a filter that is not locked will lift during the cycle and let food into the pump.
8. Run an empty cleaning cycle (1.5–2.5 hours, unattended). Nothing in the machine but the cleaner. Use the hottest cycle available, plus a Sanitise option if your machine has one. If your dishwasher has a dedicated Machine Care, Tub Clean or Self Clean cycle, use that instead.
9. Prop the door open afterwards (1 minute). Leave it on the latch overnight so the interior dries.

How often the manufacturers actually say to do this

“Clean it now and then” is the standard advice. The documentation is a great deal more precise than that, and the brands are not close to each other:

• Miele builds the interval into the machine. Its dishwashers display Sieb kontrollieren — “check filter” — every 50 programme cycles as the factory setting, and the interval is user-adjustable in the settings menu between 30 and 60 cycles. That is a manufacturer telling you, in a number, that it expects the filter to need attention roughly every seven to eight weeks in a household running the machine daily.
• Panasonic, on its Japanese built-in dishwashers, is far stricter: the residue filter (zansai firutā) comes out and is emptied and rinsed after each use, and Panasonic adds that if soil has built up around the heater cover it should be worked off with a toothbrush. Japanese machines are smaller and run more often, but the underlying logic holds everywhere — food that leaves the filter within a day never gets the chance to rot in it.
• Bosch tells owners to clean the filter every few months as a baseline, with more frequent cleaning depending on use.

Take the strictest one your patience can sustain. If you cook meat, rice or pasta regularly, the Panasonic position is not fussiness.

Why the rubber seal is the part with the evidence behind it

Of everything in a dishwasher, the door gasket is the surface with the most published work on it — and the results are the reason step 6 of the procedure exists. A 2011 study by Zalar and colleagues in Fungal Biology sampled dishwashers internationally and detected the black yeasts Exophiala dermatitidis and Exophiala phaeomuriformis in 35% of the machines examined. A later study published in PLOS ONE in 2016 found E. dermatitidis in 47% (14 of 30) of the dishwashers tested, and reported that the rubber seals were the most frequently fungus-contaminated part of the machine (57%, 17 of 30), carrying up to 10⁶ colony-forming units per square centimetre.

The operative detail for anyone holding a cloth is what those organisms tolerate. The 2016 paper describes them as surviving low and high pH, temperatures up to 60 °C or 80 °C, occasional drying out and high organic loading. That is a plain explanation of why running a hot cycle and hoping does not clear a dishwasher gasket: the conditions inside the machine are the conditions these organisms are adapted to. They come off mechanically — a brush and a cloth along the channel — or they do not come off. This is not a reason for alarm about your dishwasher; it is a reason to stop treating the seal as an optional extra at the end of the job.

The spray arms: the step nearly everyone skips

Most dishwashers have a lower spray arm, an upper arm under the top rack, and often a small third jet in the roof. Food in the jets does two things: it starves the top rack of water, so plates come out dirty and you assume the machine is failing, and it holds a pocket of rotting food inside the arm where nothing washes it out.

1. Spin each arm by hand. It should turn freely with a light push. Resistance or a wobble means something is jammed under it or the bearing is worn.
2. Check every jet. Work around the arm and clear each hole with a wooden toothpick — this is the tool Miele’s own instructions name. Push gently and pull the debris out rather than driving it further in.
3. Take the arms off if your model allows it. Many lower arms lift straight off their spindle; many upper arms release with a plastic nut that turns counter-clockwise. Check the manual — some are not designed to come off, and forcing them cracks the mount.
4. Flush a removed arm under the tap from the centre hole and let the water run out through the jets, then shake it out. You will often hear grit rattling inside.
5. Refit and spin again to confirm free rotation before you close up.

If your jets are furred rather than blocked with food, that is limescale, and it means a descaling cycle rather than a toothpick. Use a descaler approved by your machine’s manufacturer.

The documented interval for the arms, and the tool the manuals name

Spray arms have a published service interval too, and it is shorter than most people assume. Panasonic specifies that the spray nozzles on its built-in dishwashers are removed and rinsed under water monthly — not inspected, removed — along with a wipe of the door, the interior, the exhaust port and the tank edges with a well wrung-out soft cloth. Miele‘s user instructions tell owners to check the spray arms regularly for blockage by food residue or limescale and to clear the jets carefully with a toothpick or a small brush, then rinse under clear water. The toothpick is not a folk remedy; it is what the manual specifies, and the reason is that wood snaps before it does damage, whereas a straightened paper clip or a piece of wire is harder than the moulded plastic of the jet and will scrape it out of round.

That matters more than it sounds. The jets are sized to produce a specific spray pattern and pressure. Widening one with a needle or a drill bit permanently changes where the water goes, and a machine that has had its jets “cleared” that way can wash worse afterwards than it did blocked. Push debris out, not in, and stop when the hole is clear rather than when it looks bigger.

Two further notes from the documentation. Miele’s filter procedure has a step most people miss: the micro filter pulls downward off the filter combination by its plastic ring, separating into coarse, fine and micro elements that each need rinsing under running water with a washing-up brush — cleaning the assembly as one lump leaves the inner face untouched. And Panasonic’s guidance warns against pouring water or hot water directly into the cabinet and against letting water sit against the door seal, because prolonged wetting there causes staining and deformation of the packing. Wipe the seal; do not flood it.

If it still smells, the problem is the drain, not the dishwasher

A machine that has been properly cleaned and still smells of stagnant water is not draining fully, and this is a plumbing fault rather than a cleaning one. GE is explicit that dirty water sitting in the machine is an installation problem. Check these in order:

• Standing water in the sump after a completed cycle. A small amount of residual moisture is normal; a visible pool is not.
• The drain hose high loop. Installation instructions require the drain hose to rise to a high loop under the worktop, or to run through an air gap fitting on the sink deck, before it drops to the disposal or waste. Without one, dirty water siphons back from the sink drain into the dishwasher and sits there. Open the cabinet under the sink and look: the hose should climb, not run flat.
• The air gap fitting, if you have that little chrome cylinder on the sink deck. They clog. The cap and cover lift off and the insert can be pulled and rinsed.
• The garbage disposal knockout plug. If the dishwasher is newly installed, or the disposal was recently replaced, and the machine has never drained properly since, this is very likely it. Disposals ship with a plastic plug sealing the dishwasher inlet, and whoever fitted it has to knock that plug out. If it is still in place the dishwasher cannot drain at all.
• Run the disposal before every dishwasher cycle. Food sitting in a shared disposal chamber smells, and the dishwasher gets blamed for it.

The high loop has a number, and you can measure it in two minutes

“Make sure the hose loops up” is where most articles stop. The installation documentation is specific, and it is the same figure across the Whirlpool group of brands — Whirlpool, KitchenAid, Maytag and JennAir all publish the same requirement:

• The apex of the drain loop must sit at least 20 inches (50.8 cm) above the floor.
• The drain hose must connect above the drain trap in the house plumbing, not below it.
• If the loop cannot be got to 20 inches, an air gap fitting must be used instead.

Below that height the machine can siphon: waste water from the sink drain is drawn back down the hose into the sump, where it sits between cycles. That is what a persistent stagnant smell in an otherwise clean dishwasher usually is. In practice the loop is normally fastened to the underside of the worktop, which on a standard 36-inch counter puts it comfortably above the minimum — so the failure cases are the installs where the hose was simply run flat along the cabinet floor to the disposal.

Take a tape measure into the cupboard under the sink, find the highest point the hose reaches, and measure from the floor. If it is under 20 inches, that is your fault found, and re-securing the hose to the underside of the counter with a clip or a hose strap is a ten-minute job with no plumbing disconnection involved. Note also that California, Washington, Minnesota and Hawaii require a physical air gap by plumbing code regardless of what the appliance maker permits, so if you are in one of those states a high loop alone is not compliant.

One more check the manufacturers name and readers skip: GE‘s troubleshooting for a machine that will not drain properly tells you to inspect around the pump inlet screen on the floor of the tub for paper, plastic or other debris blocking the inlet — a fragment of label or the corner of a plastic wrapper is enough. That is a two-minute look with the filters already out, and it is the last thing to rule out before you conclude the pump has failed.

Bleach, vinegar and dishwasher cleaners: what is actually safe

This is where readers do real damage, so be specific about what your machine is made of before you pour anything in.

What is safe on every machine: hot soapy water, a soft brush, a dedicated dishwasher cleaner or descaler that names your brand or states compatibility, and the machine’s own hottest cycle. That combination handles every cause of odour on this page.

Keeping it from coming back

• Clean the filter monthly. Once you have done it, it is a two-minute job. Put it on the calendar or attach it to a habit — the first of the month, the day the bins go out, whatever sticks.
• Scrape, don’t rinse. Scrape plates properly into the bin, but don’t pre-rinse them spotless — modern detergents need some soil to work against, and a rinsed load often cleans worse.
• Run the machine at least every two or three days. If you genuinely can’t fill it that often, run a short rinse cycle on the part-load.
• Prop the door open on the latch after each cycle. Twenty minutes of airflow prevents most mildew.
• Wipe the gasket and the door edge weekly. Thirty seconds with a cloth.
• Run the disposal before you start the dishwasher.
• Take the spray arms off and rinse them monthly — that is Panasonic’s stated interval, and it is the one worth adopting whatever you own. Run a descaling cycle with an approved descaler if you’re in a hard water area and the jets are furring.

Frequently asked questions

How often should I clean my dishwasher filter?

Go by your brand rather than by a general rule. Miele’s machines prompt you every 50 programme cycles as a factory default, adjustable between 30 and 60 in the settings menu. Panasonic’s Japanese built-in dishwashers specify emptying the residue filter after every use. Bosch says every few months, more often with heavy use. For a typical household running the machine most days, monthly is a defensible middle, and every two to three weeks if you wash a lot of greasy pans. It takes about two minutes once it is a habit.

Can I put bleach in my dishwasher to kill the smell?

Not if the tub is stainless steel. Chloride ions initiate self-propagating pitting corrosion in the 304/316 stainless used for dishwasher tubs, the damage is permanent, and it is not covered by warranty. Bosch prohibits chlorine-based and bleach-based cleaners on its appliances outright. GE offers a dilute bleach wipe-down as one option for mildew — and a dilute ammonia wipe-down as the alternative — with an explicit instruction never to mix the two, because the combination creates toxic fumes. In practice the smell is food, not bacteria on an otherwise clean surface, so removing the food works better than disinfecting around it.

Does a cup of vinegar on the top rack work?

It masks rather than fixes. It does nothing to a clogged filter or a plugged spray arm, which is where the smell is coming from. Bosch advises against household acids including vinegar and citric acid, because of what they do to the rubber components; Miele directs owners to a descaler with corrosion protection rather than a household acid, and sells a citric-acid one of its own. Clean the filter first; if the machine is furred with limescale afterwards, use a descaler approved for your machine rather than vinegar.

Why is there water sitting in the bottom of my dishwasher?

A small amount of moisture in the sump is normal. A visible pool after a completed cycle means it is not draining. Measure the drain hose loop under the sink first: Whirlpool, KitchenAid, Maytag and JennAir all require the apex to be at least 20 inches (50.8 cm) above the floor, connected above the house drain trap, with an air gap fitting instead if that height cannot be reached. Then check the air gap fitting if you have one, look for debris on the pump inlet screen in the tub floor as GE’s troubleshooting directs, and if the machine or the disposal was recently installed, confirm the disposal’s knockout plug was actually removed. Persistent standing water with all of that ruled out is a failed drain pump, which is a service call.

My dishwasher smells but the dishes come out clean. What is it?

Usually the door edge and gasket, or the detergent dispenser. Both sit outside the wash path, so they can be filthy while the wash itself performs perfectly. The gasket is also the part with the most research behind it: a 2016 PLOS ONE study found the rubber seals to be the most frequently fungus-contaminated component in the machines it sampled, at 57% of units tested. Pull the door fully down and look at the strip of tub below the opening — that area is dry during every cycle and never gets rinsed.

Do I need a dishwasher cleaner tablet, or will detergent do?

Detergent is formulated to lift food from dishes in the wash path. A dishwasher cleaner is formulated to strip grease film and scale from the tub, the hidden pipework and the pump. For the monthly maintenance cycle, use the cleaner. For the smell itself, neither product substitutes for taking the filter out — the cleaning cycle is the last step of the job, not the whole of it.