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Why does my washing machine smell?
A washing machine smells because bacteria and mould grow in a layer of detergent residue, fabric softener and lint called biofilm. It builds up in the door seal, the detergent drawer, the drain filter and the outer tub — places water reaches but you never see. Washing cold, using too much detergent and closing the door after a cycle all speed it up.
The smell is not the machine failing. It is organic material that has been sitting damp and warm, which is close to ideal conditions for growing bacteria.
Front loaders smell more than top loaders — here’s why
Two reasons, both structural.
First, the door gasket. A front loader needs a watertight rubber seal, and that seal has a fold in it. Water, lint and detergent collect in the fold and stay there. Top loaders have no equivalent.
Second, water pooling. A front-loading drum sits horizontally, so a small amount of water always remains at the bottom after a cycle. A top-loading drum drains more completely.
If you have a front loader and it smells, you have almost certainly found the problem before you finish reading the next section.
The four places the smell actually comes from
1. The door seal (front loaders)
Peel the rubber gasket back with your fingers and look into the fold. If there is black or grey slime, that is mould, and it is the single most common source of washing machine odour. Wipe it with hot soapy water or a diluted bleach solution, then dry it.
2. The detergent drawer
Pull the drawer all the way out — most release with a catch in the middle — and look at the housing it slides into. There is usually a slimy build-up on the roof of that cavity that never gets rinsed. Scrub the drawer and the cavity, and leave the drawer slightly open between washes.
3. The drain filter
This is the one almost everyone forgets, and it is often the worst. On most front loaders it is behind a small panel at the bottom front. Put a shallow tray and a towel down first, because water will come out.
What comes out of a filter that has never been cleaned is genuinely unpleasant: lint, hair, coins, and standing water that has been there for months. Clean it every few months.
4. The outer tub
Between the drum you can see and the outer tub you cannot, there is a cavity where water circulates. You cannot reach it with a cloth. This is exactly what a tub clean cycle is for — see what tub clean actually does for the detail.
Fix it in the right order
Order matters. Running a cleaning cycle first is the most common mistake, because it does nothing about the gasket or the filter.
- Wipe the door seal and dry it.
- Clean the detergent drawer and its cavity.
- Empty the drain filter.
- Then run a hot cleaning cycle on an empty drum.
For the last step, Affresh washing machine cleaner is the standard choice — one tablet, empty machine, hottest cycle. The 12-tablet pack works out cheaper if you run it monthly, which you should.
White vinegar is the free alternative and it will handle light odour, but it does not shift established biofilm, and manufacturers disagree on it — Maytag advises against it, while LG and Samsung recommend it.
How to stop it coming back
- Leave the door and drawer ajar between washes. This single habit prevents more odour than everything else combined.
- Use less detergent. Excess detergent does not rinse away — it becomes the food supply for the biofilm. Most people use two to three times what is needed, especially with concentrated liquids.
- Run one hot wash a month. Cold washing is better for clothes and energy bills, but it does not reach disinfecting temperature. A monthly hot cycle helps — though whether your machine truly reaches its stated temperature is a separate question, covered below.
- Take laundry out promptly. Wet washing left in a sealed drum for hours is how a clean machine starts smelling again.
- Go easy on fabric softener. It is waxy and it coats the drum and hoses. If your machine already smells, stop using it for a month and see what changes.
Does a hot wash actually kill bacteria?
This is the advice everyone gives, including us — run a hot wash and it kills the bacteria. It is true in principle and unreliable in practice, and the gap matters.
The threshold. NHS England guidance is 60°C (140°F) for at least ten minutes for contaminated items. Temperature alone is not enough — it has to be held. As an alternative, the NHS suggests 40°C (104°F) combined with a bleach-based laundry product for underwear, towels and household linen.
The problem. Your machine’s dial is a request, not a guarantee. When researchers tested six household washing machines, half failed to disinfect on short cycles, and a third failed even on the longer ones. In one case a machine set to 60°C never rose above 20°C.
Modern machines are built to save energy, and heating water is the expensive part of a wash. Many reach their stated temperature briefly, or not at all — particularly on eco and quick-wash settings, which are precisely the ones most people use by default.
What to do with that:
- Use the long cycle, not the quick one, when disinfection actually matters. Duration at temperature is what does the work.
- Avoid eco settings for this purpose. They save energy specifically by heating less.
- Add a bleach-based product if you are washing something genuinely contaminated. It does not depend on your machine hitting a temperature it may never reach.
- Do not assume the label. If you want to know what your machine actually does, an oven thermometer in a jug of water through a cycle will tell you more than the manual.
For routine laundry none of this matters much — clean clothes do not need to be sterile. It matters for towels, bedding, underwear, and anything from someone who has been ill.
Frequently asked questions
How long does it take to fix? The physical cleaning is 20–30 minutes. If the smell has been there for months, expect to run two or three cleaning cycles a week apart before it clears entirely.
Can I use bleach? Yes, but never with vinegar, and check your manual first — check your manual first. Warranties generally exclude damage caused by unsuitable cleaning products, and bleach spills are a commonly cited example — but manufacturers differ on bleach itself, so the manual is the only reliable answer for your machine.
My clothes smell but the machine seems fine. That is usually the filter or the outer tub — the two places you cannot see. Clean both.
Will a hot wash on its own fix it? Not once biofilm is established. Heat helps, but the residue needs to be physically removed or chemically broken down.
