Mold in Dishwasher: Seal, Filter and Six Brands’ Rules

What you are looking at inside the dishwasher

Most marks called dishwasher mold are one of seven things, and GE publishes a note on nearly every colour. Check where it sits and whether it wipes off.

What you see	Where	What it usually is	Source
Black speckling that survives a wipe	Fold of the lower door seal	Fungal growth on trapped water and food film	Ljubljana study; GE mildew article
Clear or white goop	New gasket, tub floor	Food-grade lubricant; washes out in a few cycles	GE white grease
Red, pink or orange stain	Tub and plastic parts	Tomato staining; fades over time	GE interior staining
Green stain	Tub and parts	Dyed gel detergent	GE
White film	Everywhere	Hard water or excess detergent	GE
Grey or brown film	Tub floor and walls	Calcium or iron build-up	GE
Grey sludge, sour smell	Filter and sump	Decomposing food	Bosch; KitchenAid; Samsung AU

GE's white grease article says the goop on a new gasket keeps a stiff seal seated and need not be removed, and GE's interior staining article says citric acid will not shift tomato stains. A slimy pink film that does wipe away belongs on our orange mold page; other rooms and appliances are indexed in the mold hub.

Where dishwasher mold grows: the field data

Two University of Ljubljana studies are the published record. a 2011 Fungal Biology study by Zalar and colleagues sampled 189 dishwashers in private homes in 101 towns, 102 of them in Slovenia and the rest across Europe, the Americas, Israel, South Africa, East Asia and Australia. The authors report fungi in 62% of machines, with the black yeasts Exophiala dermatitidis and Exophiala phaeomuriformis most often, and conclude that heat, moisture and alkaline pH make dishwashers an alternative habitat for them.

the 2016 Ljubljana study in PLOS ONE, by Zupančič and colleagues, then asked where inside. In autumn 2013 the team swabbed nine user-accessible sites in 30 home dishwashers from four manufacturers, aged 1 to 8 years, right after a wash had finished. The paper reports fungi in 83% of machines irrespective of site, and Exophiala dermatitidis in 47%, primarily on the rubber seals.

The ranking cuts against most cleaning guides, which lead with the spray arms: per the 2016 paper they were the least contaminated site, while the seal, which no cycle scrubs, led. The filter was not swabbed separately, but the drain beside it was positive in 43% of machines according to the same table. The authors name the tap water feeding the machine as the most probable route in, and a 2019 follow-up in BMC Microbiology found bacteria on the seals of all 30 machines it examined. Front-load washers share the pattern of a wet seal no cycle reaches; see mold in washing machine parts.

Dishwasher filter cleaning: six brands side by side

All six brands publish filter instructions. Whirlpool and KitchenAid, both Whirlpool Corporation brands, publish the same article word for word; the others disagree on frequency, brushes and bleach.

Brand	Filter type	Cleaning frequency	Method	Source
Bosch	Removable filter with mesh screen	Every few months	Remove lower rack and spray arm, twist out filter, wash with mild soap and a soft brush	Bosch care and filter pages
Whirlpool	Manual triple filter: upper assembly plus lower filter; some self-clean	Monthly; every two weeks with daily use	Upper assembly 1/4 turn counterclockwise; rinse; soft brush, no wire brush or scouring pad	Whirlpool filter article
KitchenAid	Same text as Whirlpool	Same; whole machine about every 30 days	Same; wipe door seals with a soft cloth and warm water	KitchenAid filter, interior articles
GE	Fine (mesh plate) and Ultra Fine filters on most newer models; some self-clean	Every other month or more	Twist Ultra Fine out, rinse with warm soapy water and a sponge; brushes can damage it	GE filter article
LG	Filter under the lower basket	Per the manual’s cleaning chart	Rinse in running water without excessive force	LG filter, maintenance articles
Samsung	Coarse filter over a Micro/Fine cylinder	Regularly	Turn handle counterclockwise, rinse both, dry; Canada adds an overnight vinegar soak	Samsung Australia, Canada

Brand	Cycle or cleaner it names	Bleach position
Bosch	Bosch cleaner on the hottest, longest cycle, a few times a year	No chlorine cleaners on the stainless exterior
Whirlpool	affresh every 30 days, or 2 cups (500 mL) vinegar upright on the lower rack, no detergent	Not addressed
KitchenAid	affresh monthly or the same vinegar cycle	Not addressed; vinegar used too often could damage the machine
GE	Vinegar, citric acid or a dishwasher cleaner	Mildew wipe: 1/2 cup chlorine bleach per gallon, or 1/2 cup ammonia, never mixed
LG	Machine Clean with citric acid or a cleaner	Not addressed
Samsung	Self Clean, empty; or 8 oz vinegar on Sanitize	Avoid bleach in stainless steel interiors

GE alone publishes a bleach recipe for dishwasher mildew, warning that bleach and ammonia make toxic fumes; Samsung Canada says bleach can damage stainless interiors. Never mix bleach with vinegar or ammonia. For the chemistry, see does bleach kill mold.

How to clean dishwasher gasket mold and the parts behind it

This order reaches the hot spots first. Wear gloves; Samsung Australia warns a hand can catch at the filter.

Step	What to do	Why this differs from generic advice
1. Power off, pull the lower rack	Breaker off if water is on the floor (Whirlpool)	The worst sites are under the rack, not on the walls
2. Seal first	Lift the lower lip, wipe the fold with a soft cloth and mild soap, dry it	The seal led at 57% per the 2016 study; cycles wet it, never scrub it
3. Filter	Your brand’s removal, running water, soft brush or sponge	Wire brushes and scouring pads damage the mesh, per Whirlpool and GE
4. Sump	Sponge debris and standing water under the filter or pump cover (Bosch, GE)	The drain was positive in 43% per the same study
5. Nozzles, arms	Clear holes with a toothpick (Bosch) or paper clip (GE)	Side nozzles (50%) matter more than arms (7%), per the study
6. Door and cups	Wipe inner door and both dispensers, lids open	The door (47%, per the study) drips into the seal
7. Brand cycle	Your brand’s cleaner or vinegar cycle, empty	Finishes the drum; never reaches the seal fold
8. Refit	Lock the filter; Whirlpool says a freely turning upper assembly is not locked	Running without filters can damage the pump (Whirlpool, Samsung)

GE's door gasket article notes some gaskets stop about three inches short at the bottom by design, so the gap is not a tear, and GE's food or mildew odor article says a dishwasher does not normally retain odors, so one that persists is abnormal. A seal that stays black is a replacement part; Whirlpool's leak troubleshooting guide describes pressing in an OEM gasket and closing the door for several hours to seat it.

Black mold in dishwasher seals: why a hot cycle is not enough

Heat seems like it should settle this, but the 2016 team swabbed straight after a wash. The paper describes dishwasher fungi that tolerate low and high pH, 60 C or 80 C, drying, salt and jet pressure.

The seal fold is also the coolest, least sprayed spot in the tub. “Black mold” is a colour, not a species; see black mold vs regular mold. Either way, physically remove the film and dry the seal.

When the dishwasher leaks: the floor and the cabinet

Growth on the seal is a chore. Growth the dishwasher causes on the cabinet panel, sink base or subfloor is a water loss. The machine sits in a closed bay, fed by a supply line and drain hose behind the kick plate, so leaks are slow and hidden, and the sink base often shows it first: see mold under sink and water damaged cabinets.

Where water shows	Likely source	What gets wet	Source
Front edge of the door	Gasket, over-sudsing, spray arm misdirecting water	Floor in front, toe-kick	Whirlpool
Bottom, front center	Pump seal, sump or overfill	Floor under the machine	Whirlpool
Behind or under the cabinet	Supply hose, inlet valve, drain line	Subfloor, side panels, sink base	Whirlpool; GE
Sink air gap	Clogged sink or air gap	Sink cabinet	GE
Door hits the counter	Latches but cannot seal	Front edge	GE
Suds	Dish soap, spilled rinse aid, washed sponges	Floor in front	GE; Whirlpool

NC State Extension lists dishwasher discharge as gray water and says gray water untreated past 48 hours may become black water; our IICRC water categories page explains the standard. EPA's brief guide to mold says dry water-damaged materials within 24 to 48 hours, and points growth over about 10 square feet to its larger guidance.

Which situation are you in

1. Speckling on the seal, door or cups; floor dry. Run the eight steps. This is maintenance.
2. Musty smell, nothing visible. Clean the filter and sump. Dirty water sitting in the tub between uses points, per GE, to the drain hose high loop or air gap.
3. Seal still black, cracked or flattened. Replace it with the OEM gasket.
4. Water on the floor or a damp toe-kick. Stop, shut water and power, and locate the leak with the table above.
5. Swollen cabinet panel, stained sink base, cupped flooring, growth outside the tub, or a smell that returns within weeks. Escalate: this is a water loss needing moisture readings and a drying plan, sized against EPA’s 10 square foot line.

Prevention that the sources support

Habit	Who says so	Why it helps here
Filter on your brand’s interval	Whirlpool, KitchenAid, GE, Bosch	Starves the sump and drain
Run at least once a week	GE mildew article	GE says this usually prevents mildew
Scrape, do not rinse	GE deep clean guide	Rinsed dishes can fool the sensor into a lighter wash
Inlet water at least 120 F	GE deep clean guide	Detergent dissolves fully
Automatic detergent only	GE; Whirlpool	Dish soap suds push water out
Inspect the gasket for tears	GE	A worn seal leaks
Softener at 15 grains or more	KitchenAid	Mineral film holds water
Indoor humidity below 60%	EPA brief guide	The seal fold dries faster

Propping the door open is widely repeated, but none of the six brand pages cited here states it.

For contractors

A moldy seal is not a remediation scope. The job starts where the dishwasher put water into the cabinet bay, sink base or subfloor; document the source before the machine is pulled.

Item	What to record	Why an adjuster asks
Source	Photo of the leak point, hose and valve condition	Failed part versus installation
Appliance	Model and serial; Whirlpool says they are on the tub frame	Ties the loss to the unit
Category	Gray water per NC State; note elapsed time	Past 48 hours it may be treated as black
Moisture map	Toe-kick, both side panels, sink base, floor, subfloor	Defines what is wet
Growth	Location and approximate area	Scope against EPA’s 10 sq ft line
Line items	Pull and reset dishwasher, remove toe-kick and panels, dry, clean, replace	Each is its own estimate line

Coverage turns on policy wording. Owners should read their policy and ask their state insurance department or a licensed professional; contractors should record when the leak started.

Questions people actually ask

Is it safe to use a dishwasher with mold in it?

Clean it before the next load. The Ljubljana studies found fungi concentrated on the door seal, side nozzles, door and drain, and only one species on washed dishes. Scrub the seal, clean the filter and sump, and run your brand’s cleaning cycle. Questions about a person’s health belong with a doctor; CDC publishes general mold guidance.

How do I get rid of black mold in my dishwasher seal?

Lift the lip of the lower door seal and wipe the fold with a soft cloth and mild soap, then dry it, as KitchenAid describes. GE adds a mildew wipe of 1/2 cup chlorine bleach per gallon, but Samsung says avoid bleach in stainless interiors, so follow your brand. A seal that stays black or is torn needs an OEM replacement.

Why does my dishwasher keep getting moldy?

The same places stay wet and fed between cycles: the seal fold, the sump and the drain. The 2016 study reports fungi in 83% of 30 machines swabbed right after a wash, and names the household water supply as the likely route in. Clean the filter on your brand’s interval, run the machine weekly as GE advises, and check for standing water.

How often should I clean my dishwasher filter?

Whirlpool and KitchenAid say once a month, or every two weeks for a large family or daily use. GE says every other month or more depending on usage, and Bosch says every few months. LG points to the chart in your manual and Samsung says regularly. Clean it sooner if dishes come out gritty or the machine smells.

Does the sanitize cycle kill mold in a dishwasher?

Do not rely on it. Samsung Canada says its Sanitize rinse reaches 163 F, but the Ljubljana researchers swabbed machines right after a cycle and still found fungi, describing species that tolerate 60 C to 80 C. The seal fold is also the least sprayed part of the tub, so scrubbing the seal and filter does the work.

Can a leaking dishwasher cause mold under the cabinet?

Yes. Whirlpool lists the supply hose, inlet valve and drain line as sources of leaks behind or under the cabinet, where water reaches the subfloor and side panels unseen. EPA says dry water-damaged materials within 24 to 48 hours. A swollen panel or damp toe-kick means a water loss, not an appliance clean.