Why does my front-load washer smell but my old top-loader never did?

The airtight rubber door seal and low water use that make front-loaders efficient also trap water in the gasket and never let the drum dry out. That damp, sealed space grows biofilm. Top-loaders breathe through the lid and use more water, so they rinse cleaner and dry faster.

Does running a hot cycle with vinegar actually work?

Yes, for a sour or musty smell. Heat plus the acid in white vinegar breaks down the detergent and softener residue the biofilm feeds on. A washer cleaning tablet works the same way. Neither does anything for a sewer smell, that one is a drain problem, not a drum problem.

Is it safe to leave the washer door open between loads?

Yes, and it is the single best thing you can do. Leaving the door and detergent drawer open lets the gasket and drum dry out so mildew cannot grow. If small kids or pets are around, leave it open only when you can keep an eye on it.

Why does my washer smell like rotten eggs or sewer?

That is sewer gas, not biofilm. It comes from a dried-out or missing P-trap on the washer standpipe, a drain hose shoved too far down and sealing the air gap, or a venting problem in the house plumbing. Refill the trap with water first. If other drains smell too, get a plumber.

Can a musty washing machine make my clean clothes smell?

Yes. Clothes washed in a fouled drum come out smelling sour or musty even though they are clean, because they pick up the biofilm odor. Clean the machine first, then re-wash the affected laundry. If the clothes still smell after that, the odor has soaked into the fabric and needs separate treatment.

Washing machine smells musty or like sewer? Here's the fix

Mildew & Musty · By Odor Removal Experts · Updated June 2026 · Cleveland and Northeast Ohio

If your washing machine smells musty, the problem is almost always a film of detergent, fabric softener, and mildew sitting in places water never fully rinses: the rubber door gasket, the detergent drawer, the drum boot, and the drain. If it smells more like sewer or rotten eggs, the source moves to the drain hose, the standpipe, or the trap behind the machine. Two different smells, two different fixes, and you usually need to handle the mechanical side before the odor goes away.

On the jobs we get called for around Greater Cleveland and Akron, the musty washer is nearly always a front-loader. The high-efficiency, low-water design and the airtight rubber seal are great for your water bill and terrible for drying out, so gunk and biofilm grow in the folds of the gasket. We will walk through exactly where it hides and how to clear it, and we will be honest about when the smell is in the laundry room itself and not the machine.

The short answer

A washing machine smells musty from biofilm in the door gasket, drawer, and drum, and smells like sewer from a dry drain trap or standpipe. Clean the gasket and drawer and run a hot tub-clean cycle for the musty smell, and refill the standpipe trap for sewer gas. Leave the door open to dry between loads.

Musty is biofilm in the gasket and drum; sewer is a drain-gas problem
Wipe the gasket folds, then run a hot cycle with vinegar or a tablet
Refill a dry standpipe P-trap for a rotten-egg smell
Leave the door and drawer open to dry between loads

Why your washing machine smells musty or like sewer

A musty washer smell is biofilm. Liquid detergent and fabric softener leave a slimy residue, that residue feeds mildew and bacteria, and the warm, damp, sealed drum is the perfect place for it to grow. Front-load washers get the worst of it because the rubber gasket around the door traps water in a lip at the bottom, and that water never fully dries between loads. Pull the gasket back and you will often find black or gray slime, lint, a forgotten sock, and sometimes standing water.

A sewer or rotten-egg smell is a different animal. That is drain gas, not biofilm. It comes from the drain hose, the standpipe the hose feeds into, or a dry or missing P-trap behind the washer letting sewer gas drift back up. If you only smell it during or right after a drain cycle, the problem is in the plumbing, not the drum. Mixing the two up is the most common mistake we see, and it is why people scrub the gasket for weeks and the sewer smell never moves.

Musty or sour smell: biofilm in the gasket, drum, detergent drawer
Sewer or rotten-egg smell: drain hose, standpipe, or a dry P-trap
Too much liquid detergent or softener feeds the residue
Cold-water-only washing never gets hot enough to break the film down
Door and drawer kept shut after a load, so nothing dries

Clean the gasket, drawer, and drum (the musty fix)

Start with the gasket, because that is where most of the smell lives. Work through the parts water never fully rinses, then run the drum itself.

Clean the gasket first. Peel the rubber boot back at the bottom and wipe out every fold with a cloth dipped in warm water and a little dish soap, clearing the lint, hair, and slime from the lip where water pools.
Get into the seams. If it is heavily fouled, use a 50/50 white vinegar and water mix and an old toothbrush to reach the seams.
Rinse the detergent drawer. Pull the drawer all the way out, rinse it under hot water, and clear the slot it sits in, since that channel grows the same film.
Run a hot tub-clean cycle. Use the machine's self-clean or tub-clean cycle, or the hottest, longest empty cycle, with a washer cleaning tablet or two cups of white vinegar, then follow with a second empty hot rinse.

Do not mix vinegar and bleach

Never combine vinegar and chlorine bleach. We do not use chlorine bleach for this anyway, since it is hard on the rubber gasket and only masks the smell.

If your clothes keep picking up the odor, our guide on what to do when clothes still smell musty after washing covers the laundry side, and how to get mildew smell out of clothes and towels handles fabrics that already soaked it up.

If it smells like sewer, check the drain

When the smell is sewer, not sour, stop cleaning the drum and look behind the machine. The washer drain hose should hook over and into a standpipe that has its own P-trap, the same U-shaped bend under your sink. That trap is supposed to hold a plug of water that blocks sewer gas. If the trap has dried out (common on a machine that sat unused), or the hose is jammed too far down into the standpipe and seals off the air gap, sewer gas comes straight back into the room and into the drum.

Run a bucket of water down the standpipe to refill a dry trap and see if the smell clears. Make sure the drain hose is not shoved all the way to the bottom of the standpipe, it should sit a few inches in with an air gap. If you get a sewer smell from other drains in the house too, this is a plumbing-vent issue and not just the washer, and that is a plumber's call. The same drain-gas logic shows up in our guide to a sewage smell in the basement.

Pour water down the standpipe to refill a dried-out P-trap
Do not jam the drain hose all the way to the bottom of the standpipe
Check that the standpipe is actually vented
Smell from multiple drains means a vent problem, get a plumber
A backed-up or partly clogged drain line can push gas back too

Keep the musty smell from coming back

The machine grew the smell because it never dries out and it is over-fed with product. Fix both. Use less detergent, about half what the cap suggests for a high-efficiency washer, and switch to powder or cut the fabric softener, which is the stickiest residue of all. Run a hot tub-clean cycle once a month. Most important and least done: leave the door and the detergent drawer open between loads so the drum and gasket air out. Wipe the gasket dry after a heavy or warm load.

Do not let wet laundry sit in the drum overnight. That is how a clean machine starts smelling sour again in a single load. If your laundry room is in a damp basement, the air around the machine matters too, and a basement that already smells musty will keep re-fouling everything in it.

Use half the detergent, skip or cut liquid fabric softener
Leave the door and drawer open to dry between loads
Run a hot clean cycle monthly
Move laundry to the dryer promptly, do not let it sit wet
Keep a damp laundry room dehumidified

When the smell is in the room, not the machine

Sometimes you clean the washer top to bottom and the musty smell is still there, because it was never only the machine. A washer that leaked or overflowed at some point can leave odor in the drywall, the baseboard, the subfloor, or the carpet of a finished laundry area, and a clean drum will not touch that. Same if the laundry room is in a damp Northeast Ohio basement that smells musty on its own. At that point the source is the room, and the appliance was just the loudest part of it.

That is the work we actually do. After the mechanical side is handled, we find the source with the smell and treat it with green, non-toxic methods: enzymatic and oxidizing treatments on porous surfaces, occupied-safe hydroxyl generators to break down what is airborne, and HEPA plus activated-carbon scrubbing to pull the rest. No ozone, no chlorine, no masking. If you want the lingering odor gone for good rather than chased around, that is our musty odor removal service.