Mold in a Washing Machine: The Gasket, the Smell, and the Fix That Holds (2026)

Why the Machine That Cleans Everything Grows Mold

A washing machine is a sealed, warm, wet box with a steady food supply. Detergent that does not fully dissolve, fabric softener, body oils and lint settle in the places water does not drain — the folds of the door gasket, the detergent drawer, the drain pump filter — and stay damp between loads. Mold does not need anything else. Front-loaders get it worst because the rubber door seal that makes them water-tight also traps a puddle at the bottom of every wash; top-loaders get it in the dispenser and under the rim.

The smell arrives first: a musty note on towels that just came out of the wash. Then the black film in the gasket folds. Neither is a defective machine. Both are a machine that is never allowed to dry.

Where It Lives

The Cleaning That Actually Works

EPA's guidance for mold on hard surfaces is to scrub it off and dry the surface, and a washing machine is hard surfaces all the way down. The order matters, because cleaning the drum before the gasket just re-seeds it.

1. 1Gasket first. Pull the seal back with your fingers and wipe every fold — there are usually two or three channels — with a cloth wet with diluted bleach (about 1 cup per gallon, per CDC guidance for mold cleaning) or a commercial washer cleaner. An old toothbrush reaches the inner channel. Gloves and an open window; bleach fumes in a small laundry room are unpleasant. A gasket with mold grown *into* the rubber — black that will not wipe off — is replaced; it is a $30–$80 part on most machines and the folds are unreachable once the colony is inside them.
2. 2Drawer and cavity. Most drawers lift out with a release tab. Scrub the drawer and the slot it came from; the back of that cavity is where the pink and grey slime lives.
3. 3Drain pump filter. Behind the small panel at the bottom front. Towel down, shallow tray under it, unscrew slowly — a cup or two of water comes out — and clear the filter. Most people have never opened this. It is where the smell usually is.
4. 4Hot empty cycle with a washer-cleaning tablet or about a cup of household bleach. Longest, hottest program the machine has. If the machine has a *tub clean* cycle, that is what it is for.
5. 5Dry it. Wipe the gasket and glass, and leave the door and drawer open.

Vinegar is a common alternative in the drum — it kills much of what grows there — but not in the same cycle as bleach, and repeated vinegar cycles are hard on rubber seals. One or the other, and bleach is the one that reaches the gasket.

The Three Habits That Keep It Gone

Cleaning is the easy half. The machine grows the same colony back in six weeks unless the conditions change.

• Leave the door and the drawer open between loads. The single most effective step, and the one people resist because it looks untidy. A front-loader with the door shut holds a puddle in the gasket for days.
• Use HE detergent at the dose on the cap, not more. Over-dosing is the residue. High-efficiency machines use less water; the extra detergent has nowhere to go.
• Run one hot cycle a month — a tub-clean cycle or an empty hot wash with a washer cleaner — and empty the drain filter every couple of months.

Wipe the gasket dry at the end of wash day and the colony has nothing to work with.

When the Machine Isn't the Problem

A laundry room that is itself damp grows mold on walls, ceilings and the back of the machine — condensation streaks, a musty smell that is *not* coming from the drum, a hygrometer reading over 60%. That is a ventilation problem, and the humidity guide covers the targets and the equipment. Mold on the laundry room wall follows the wall rules, not the appliance rules. A leaking supply hose behind the machine soaks the wall and floor quietly for months — check the hoses when you check the filter, and replace rubber hoses over five years old with braided stainless ones.

Bottom Line

Gasket, drawer, filter, hot cycle, dry — then leave the door open. Washing machine mold is a habit problem dressed as a cleaning problem, and the machines that stay clean are the ones that are allowed to dry. If the smell survives a proper cleaning and an open door, the gasket has mold in the rubber and gets replaced.