Top-load washer smells musty or like mildew? Where the gunk hides
Musty top-loader? Waxy detergent and softener residue builds up where a clean cycle can't scrub. Where it hides, and the clean that reaches it.
You ran the clean cycle or a cup of vinegar, maybe twice, and the musty, wet-dog smell is back. Most advice online is written for front-loaders and their rubber door seal, which your machine doesn’t have. Top-loaders grow the same film, just in different places. (Eggy or sewer rather than musty? See why a washer smells like rotten eggs or sewage.)
Why does a top-load washer smell musty?
The smell is biofilm: bacteria and fungi, mould (or mold) and mildew among them, living in a thin layer of leftover detergent and softener. Modern machines often have many plastic parts, which researchers call ideal for biofilm to cling to. The residue thickens into scrud, the gunky, waxy build-up that can also mark your clothes.
That isn’t a bad clean on your part. One cycle on its own kills some growth but leaves the crust and the dead film behind. Three things keep feeding what’s left, while a lid left shut between washes keeps it all damp:
- Cold-only washes. Soil and detergent build up faster when nothing ever runs warm or hot; Samsung also names cold-only washing as a cause.
- Too much detergent, which speeds the build-up, or non-HE detergent in a high-efficiency (HE) machine, which leaves a film.
- Fabric softener, which adds to the waxy scrud.
Where a top-loader hides the gunk
Three places you can scrub by hand, and one only a cycle reaches. Unplug the machine before you lift anything off.
The fabric softener dispenser
If your agitator (the tall post in the middle) carries a softener cup on top, liquid softener residue builds up in it. On a Speed Queen, squeeze the lower part and pull straight up; on other machines, follow your manual. Soak the pieces in warm, soapy water, scrub with a toothbrush and rinse. If your dispenser is a pull-out drawer instead, scrub the slot it sits in too.
Inside the agitator, or under the impeller
With the cup off, brush inside the agitator column. Some machines hide a lint screen here or at the rim; lift the agitator off only if your manual shows how.
No agitator? The makers’ guides cited here don’t cover cleaning under an impeller (the low plate in its place); the clean cycle below is your route.
The rim and the underside of the lid
Soapy water splashes up the tub walls and dries into a sticky band above the waterline; wipe it, the rim and the lid’s underside with a warm, damp cloth.
Between the drum and the outer tub
The drum sits inside a solid outer tub, and residue collects in the gap, out of reach without a strip-down. Only a cycle gets there. It won’t scrub the gap clean, but run regularly, with those three habits fixed, it keeps the film down.
How to clean a smelly top-loader, in order
Before you start, pick one cleaner for your build-up. For the gap, the choice matters: an oxygen-bleach cleaner tablet lifts film off surfaces, while chlorine bleach kills it but leaves it in place.
- Do the three hand-cleans first, so the cycle flushes what you’ve loosened.
- Empty the drum and run the clean cycle (or the hottest, fullest wash) with that one cleaner, as your manual says; two makers’ versions are in the table below. Never mix bleach with vinegar or ammonia, or run one straight after the other.
- Wipe out leftover residue with paper towels (Samsung’s step), then run a rinse and spin. Loosened residue may come away in flakes; wiping and rinsing keeps them off your next load.
- Leave the lid open to dry.
| Maker | Cycle | Cleaner and where it goes |
|---|---|---|
| Whirlpool | Clean Washer | One affresh tablet in the drum (Whirlpool says basket), not the dispenser, or 1 cup (236 ml) of liquid chlorine bleach; more bleach can damage the washer |
| Samsung | Self Clean, about an hour on top-loaders | Liquid chlorine bleach to the max line in the detergent compartment, not the bleach one; never with laundry inside |
Whirlpool names no compartment for the bleach: use the one your manual gives. If your manual allows a washer-cleaner tablet, that’s the one to use for the gap; otherwise follow its bleach instructions. Other makers: see your manual.
Keep it from coming back
The full top-loader routine:
- An occasional hot or very hot wash, not only cold, as CHOICE advises.
- The maker’s detergent dose, and HE detergent in an HE machine. LG’s figure for its machines is 2 tablespoons (about 30 ml), or 1 if concentrated.
- Softener sparingly, or not at all.
- Lid open between washes; laundry out when the cycle ends.
- Monthly, or every 30 washes if sooner (Whirlpool’s interval): wipe the softener dispenser, the agitator column if you have one, and the rim, then run the clean cycle.
The gap you can’t reach is why it’s monthly. For how fast the film regrows, why every new cleaner seems to work for a fortnight, and when an older machine needs a service visit or replacing, read why one big clean never stays clean.
Still musty after all that?
- Repeat the clean cycle weekly until the smell goes, which is LG’s advice for bad cases.
- If it holds on, suspect the gap behind the drum. LG says severe cases may need a professional clean that its own technicians don’t do, so ask a local appliance service whether they offer one.
- Machine fine but laundry still musty? See why clothes smell musty after washing.