Why your washing machine smells (and how to fix it properly)
- 1 day ago
- 5 min read
If your washing machine smells worse than the clothes you’re putting into it, you’re not imagining it.
That damp, slightly musty smell that hits you when you open the door… laundry that comes out almost clean but not quite fresh… and the frustrating part — your washing machine smell keeps coming back.
You clean the drawer, run a hot wash, maybe even use a cleaner… and yet within a week or two, the smell is back again.
So what’s actually going on?
Quick answer
Washing machines smell because of a build-up of moisture, detergent residue and bacteria. In hard water areas, limescale makes the problem worse by trapping that build-up inside the machine — which is why your washing machine smells even after cleaning it.
Why washing machines smell
Most washing machine smells come down to a simple combination: moisture + residue + time.
Inside your machine, you’ve got the perfect environment for build-up.
Warm, damp conditions allow bacteria and mildew in the washing machine to grow, especially in hidden areas like the rubber seal and detergent drawer.
⁕There’s also one really common habit that quietly makes things worse — and I was completely guilty of it.⁕
For years, I ran everything on a 60 minute 40°C cycle.
It felt like the sensible default — quicker, cheaper, and “good enough” for most loads. But over time, it actually contributed to that musty washing machine smell.
That’s because lower temperatures don’t break down residue as effectively, and without the occasional hotter wash, that build-up isn’t properly cleared out. It just sits there, layer by layer, creating the perfect conditions for smells to develop.
Over time, all of this leads to:
Detergent and fabric conditioner residue
Dirt and lint from clothes
Bacteria and biofilm build-up
That’s what causes that musty, unpleasant washing machine smell.
Why the smell keeps coming back (this is the bit most people miss)
Here’s where it gets interesting — and where hard water comes in.
If you live in a hard water area (around 60% of the UK), your washing machine smells bad for an extra reason.
Alongside detergent residue, there’s also limescale. Limescale forms a thin, chalky layer inside your machine — on the drum, heating element, and internal pipework.
And that layer acts like a trap.
Instead of everything being rinsed away cleanly, residue sticks to it. Bacteria cling to it. And even after you “clean” the machine, that underlying layer is still there… holding onto the problem.
So the smell comes back.
Signs it’s a limescale-related issue
Not every smelly washing machine is caused by limescale — but there are some tell-tale signs:
The smell returns quickly after cleaning
You notice white, chalky residue inside the drum or drawer
Your laundry smells dull rather than fresh
Your laundry feels stiff or scratchy after washing
You live in a known hard water area
If that sounds familiar, a surface clean alone won’t fix it.
How to clean a washing machine that smells (properly)
If your washing machine smells bad, you need to tackle both the visible grime and the hidden limescale.
Start with the basics:
Clean the rubber door seal thoroughly — this is one of the biggest hotspots for trapped moisture and residue.
Pull it back and wipe inside.
Remove and rinse the detergent drawer.
Then run a hot wash (60–90°C) with an empty drum.
And here’s the key step most people skip: ⁕Descale the machine⁕
This is what actually fixes a washing machine smell that keeps coming back. Descaling breaks down the limescale layer inside, so all that trapped residue can finally be flushed away.
You can either use a specially formulated washing machine descaler, or a simple natural option like citric acid.
The exact steps vary slightly depending on the product, but the overall process is straightforward.
To descale with citric acid:
Add 3–4 tablespoons directly into the empty drum
Run a hot cycle (60–90°C)
No laundry inside
Without this step, you’re only cleaning the surface — not the root cause.
We recommend citric acid for descaling throughout your home. It's safe to use on kettles, taps, toilets, showers and more.
How to stop your washing machine smelling again
Once it’s properly clean, keeping it fresh is much easier. A few simple habits make a big difference:
Leave the door and drawer slightly open after washes
Avoid overusing detergent
Run an occasional hot wash ideally 60°C every week or two — throw in your bedding and towels, as this temp helps tackle bacteria and germs on them
Descale regularly, especially in hard water areas
If you want to go a step further, the only way to stop limescale building up altogether — not just in your washing machine, but in your kettle, shower, pipes, and even on your skin and hair — is to remove the minerals that cause hard water in the first place.
That’s where a water softener comes in.
When it might not be limescale
From our experience running a plumbing business in the South, this is one of the most common causes of a smelly washing machine in hard water areas.
But if your washing machine smells strongly of sewage or rotten eggs, it could be a drainage issue rather than build-up inside the machine.
In that case, it’s worth checking the waste pipe or getting it looked at by a plumber or white goods engineer.
If your washing machine smell keeps coming back…
If your washing machine smell keeps coming back no matter what you try, it’s usually not because you’re cleaning it wrong — it’s because something underneath hasn’t been removed.
In hard water areas, that “something” is often limescale.
Deal with that, and the rest becomes a lot easier.
FAQs about washing machine smells
Why does my washing machine smell even after cleaning it?
Because surface cleaning doesn’t remove limescale inside the machine. In hard water areas, that layer traps residue and bacteria, so the smell quickly returns.
Can a dirty washing machine make clothes smell?
Yes — if there’s build-up inside the drum or pipework, your clothes can come out smelling musty even after a full wash.
Can I use vinegar to descale my washing machine?
Vinegar can help with light build-up, but it’s not strong enough to remove heavy limescale. For a proper clean, a descaler or citric acid is more effective.
How often should I clean my washing machine?
A quick clean (seal and drawer) once a month is usually enough, and descaling every 1–3 months is key in hard water areas.
Why does my washing machine smell like sewage?
A sewage or rotten egg smell usually points to a drainage issue rather than residue inside the machine. This could be caused by a blocked or poorly connected waste pipe, or stagnant water in the system. If the smell is strong or persistent, it’s worth having it checked by a white goods engineer.
Author bio: Lucinda Smalley is the founder of Hard Water Home, a UK-based consumer site helping households in hard water areas understand the challenges and solutions more easily — and make smarter choices for their health and homes. Based in Poole, she also co-runs an award-winning plumbing company, giving her first-hand insight into how water quality affects everything from appliances to skin and hair. When she’s not writing, she’s happiest at the beach with her family and a good cup of coffee (minus the floaty bits!). More about us ➡
