You run a hot cycle, add detergent, and pull out towels that smell like a damp basement. If that sounds familiar, there may be mold in your washing machine, or at least some other microbial buildup, quietly growing in the warm, wet spots you never see.
It’s not as rare as it sounds. In a 2015 study of 70 household washing machines in Slovenia, 79% tested positive for fungi, with samples taken from detergent drawers and rubber door seals. A 2021 review in Applied and Environmental Microbiology cites the study. That doesn’t mean 79% of washers have visible mold, but it shows how readily fungi settle into the damp parts of a machine.
Here’s how to tell what you’re dealing with, how to clean it without damaging your machine or your lungs, and how to keep it from coming back.
How to tell if your washer has mold
- Check the door seal. On a front-loader, pull back the rubber gasket and look in the folds for black, green or brown spots and a slimy film. Water and lint collect there after every load.
- Look at the detergent drawer. Slide it out if it comes free and check the cavity behind it too. Dark spots and gunk in there are common.
- Look under the lid. On a top-loader, check the underside of the lid, the rim of the tub and any dispensers.
- Use your nose, but don’t stop there. A musty or sour smell coming from the machine, or from clothes that just came out of it, is the classic warning sign.
The same 2015 study found that machines with fungi were most often run at 40°C (104°F), while fungus-free machines were most often run at 60°C (140°F). Detergent and softener residue and wash temperature were the most important factors the researchers identified. That’s an association, not proof that a hot wash prevents mold, but it’s one reason a regular hot cleaning cycle is worth it.
Before you clean: check what your manual says about bleach
Here’s what most cleaning guides skip. Appliance brands don’t agree on bleach.
- Whirlpool: for stubborn mold or mildew on the gasket, its guide calls for 3/4 cup of liquid chlorine bleach in 1 gallon of warm water, left on for about 5 minutes before scrubbing.
- LG: its support page says to avoid chlorine-based or acidic washer cleaners because they may cause discoloration or corrosion, and recommends an oxygen-based washing machine cleaner instead.
Look up your model in the manual or on the manufacturer’s support site before you pick a product. If you can’t find guidance, start with the manufacturer’s recommended cleaner or cleaning cycle, if one is specified for your model.
How to clean mold from your washing machine
Start with the gentlest option that works and move up only if you need to.
- Empty the drum and protect yourself. Take out all laundry and put on gloves and eye protection. The CDC recommends at least an N95 respirator, gloves and goggles for mold cleanup, so consider a respirator if you’re disturbing visible mold. Ventilate the room while you clean.
- Scrub the easy spots first. Wipe the gasket folds, the door glass and the drawer cavity with warm water and detergent, then pull the drawer and scrub it in the sink. The EPA’s advice for mold on hard surfaces is the same: scrub with detergent and water, then dry completely.
- Treat what’s left, the way your manual says. Use the bleach solution your manufacturer specifies, or an oxygen-based washer cleaner if that’s what it recommends. Never both at once.
- Run the cleaning cycle. Use the tub clean or self-clean setting if your machine has one. If not, use the hottest wash your manual allows, with the cleaner where the manual says to put it.
- Rinse, wipe and dry. Add an extra rinse if your machine offers one, wipe the gasket and the rim of the drum dry, and leave the door and drawer open.
If you have allergies, asthma, lung disease or a weakened immune system, consider having someone else do the cleanup. The CDC lists those groups as being at greater risk from mold exposure.
Mold that keeps returning after a thorough cleaning may need a service technician. Look around the machine too. A slow leak from a hose or drain can grow mold on the wall or floor behind it. For general household mold cleanup, the EPA says a moldy patch smaller than about 10 square feet, roughly 3 feet by 3 feet, is usually manageable on your own, while larger areas or water damage call for professional advice. Our guide to ways to make your home less prone to damage covers catching leaks early.
See also
The fix most people skip: let it dry
Mold needs moisture. A washer that’s shut tight and damp is the ideal home for it. A dry one isn’t.
- Leave the door and drawer open after every load. Whirlpool and LG both recommend it so air can circulate and the inside can dry.
- Wipe the gasket. Whirlpool suggests a dry cloth after each load and a damp one every few loads.
- Unload promptly. Wet clothes left sitting in a closed drum are a recipe for musty laundry.
- Use the right detergent, in the right amount. Check your manual for the type your machine needs and the dose for your load size.
- Clean on a schedule. Whirlpool suggests a deep clean about once a month or every 30 cycles, and LG suggests running Tub Clean every 30 uses.
- Consider a dehumidifier. Whirlpool suggests one if your laundry room stays damp.
More routines that keep the whole house fresh are in our spring cleaning tips.
The bottom line
Musty laundry is a signal, not a diagnosis. Look for visible mold in the gasket, drawer and under the lid, check what your manufacturer says before reaching for bleach, and never mix cleaners. Then keep the door open, wipe the seal and clean on a schedule, and the smell has a hard time coming back.
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