Smelly Washing Machine? Causes and the Fix in 5 Steps

Where the smell comes from

Modern machines and detergents are designed for low temperatures. That saves energy but has a side effect: at 20, 30 or 40 °C many bacteria survive. Together with skin cells, fibres, grease and leftover fabric softener and liquid detergent, they form a slimy biofilm. It sits wherever things never dry properly: in the fold of the rubber door seal, in the detergent drawer, in the filter and in the outer drum behind the one you can see. As the bacteria break down organic matter, they produce that musty or rotten smell.

It’s made worse by:

• Washing almost only at 30 or 40 °C and rarely at 60 °C.
• Liquid and colour detergents, which contain no bleach.
• Lots of fabric softener.
• Keeping the door and drawer shut after washing.
• A blocked filter holding dirty water.

The fix in 5 steps

1. Clean the door seal

Gently pull back the rubber seal and look inside the fold. Water, hair, fluff, coins and even socks collect there, often with black grime. Wipe it out with warm water and a little washing-up liquid or all-purpose cleaner, then dry it. Black marks that won’t budge are often mould, so treat them with 70 % alcohol. If staining remains it has set into the rubber, but it’s usually harmless once the smell has gone.

2. Clean the detergent drawer

Pull the drawer right out. Most models have a release tab, and your manual will show where. Rinse it in warm water and scrub it with an old toothbrush. Don’t forget the housing the drawer sits in: the top of it often hides the worst build-up. Shine a torch in and clean it with a brush or cloth.

3. Clean the filter

It’s usually behind a small flap at the bottom front. Unplug the machine and lay down a towel and a shallow tray. If there’s an emergency drain hose, release the water through it first. Then slowly unscrew the filter, remove fluff, hair and objects, rinse it under the tap and screw it back firmly. Check afterwards that it doesn’t leak.

4. Run an empty hot wash

Now the actual clean. Run an empty cycle at the highest temperature (60–90 °C, ideally a cotton cycle) with one of these:

• Biological washing powder (a normal dose): the oxygen bleach breaks down biofilm.
• A washing machine cleaner used as the pack directs. This is handy when the smell is strong.

Repeat once if the smell is bad.

5. Let it dry

After the cycle, wipe the seal dry and leave the door and drawer open. Do this after every wash from now on.

Does it smell like drains?

If it smells more like sewage than mustiness, the cause may be the waste connection rather than the machine. A dry or missing trap lets drain gases rise. Check that the drain hose is fitted with a proper hook or connected to a trap. If it’s connected under the kitchen sink, that trap may be blocked.

When to call an engineer

If the smell returns within days of a thorough clean, the machine doesn’t drain properly, or water stays in the drum, the drain pump or a hose may be blocked. Get it checked, especially while it’s still under warranty.