How to Clean a Smelly Washing Machine: Step-by-Step

My washing machine started smelling like a wet dog sometime in March.

I noticed it the way you notice most household problems, which is to say I ignored it for about six weeks. Then one Saturday I pulled out a load of towels, and they smelled worse coming out than they did going in. Not faintly musty. Properly sour, like they’d been sitting in a hockey bag since February.

I stood there in the laundry room holding a towel and finally did the obvious thing. I leaned into the empty washer and took a breath. The towels were innocent. The smell was coming from the machine itself.

This is one of the most common appliance complaints there is, and the fix is straightforward once you know where the smell actually lives. It took me about an hour, most of it waiting for wash cycles to finish. Here is the whole process.

Why Does Your Washing Machine Smell Bad

The culprit is biofilm, which is a layer of bacteria, leftover detergent, fabric softener residue and moisture that builds up on the inside surfaces of the machine. Every load you run feeds it a little more. It is not just surface grime. It is a living layer, and warm, damp darkness is exactly where it wants to be.

Front-load washers get it worse. The airtight rubber seal that makes them water efficient also traps moisture inside after every cycle, and the folds of the gasket collect water and debris you never see. Consumer Reports has documented the problem for years. In their Annual Product Reliability Survey, eight percent of the washer failures or repairs reported by readers were due to mould. Top-loaders breathe better and tend to drain more fully, but they are not immune. Detergent buildup and stagnant water will sour any machine that gets ignored long enough.

Two habits make it worse than it needs to be. Washing everything in cold water lets bacteria thrive, since they are never hit with real heat. And using too much detergent, which is easy to do with bulk jugs, leaves residue that the rinse cycle never fully clears.

If your clothes are coming out smelling musty on their own, the problem is often why clothes smell after washing rather than the machine itself.

What You Need to Clean Your Washing Machine

Nothing specialized. You likely own most of this already:

• Washing machine cleaner tablets or powder, the kind your manufacturer recommends. White vinegar (2 cups) works as the DIY alternative, with one caveat below.
• Baking soda, about half a cup
• Dish soap
• An old toothbrush or small scrub brush
• Two microfibre cloths
• An old towel you do not care about
• Rubber gloves, if you want them

A note on vinegar before we start. It is the internet’s favourite washer cleaner, and it does work on mineral buildup. But some manufacturers explicitly warn against it. Siemens, for example, tells owners not to use vinegar or citric acid on the seal because they can attack the rubber material. Your manual is the final word for your machine.

Whatever you clean with, never mix vinegar and bleach. Together they create chlorine gas, which irritates the eyes, skin and lungs and is genuinely dangerous. Different days, different cleanings.

Step 1: Run an Empty Hot Wash Cycle

Take everything out of the machine. All the way empty.

Add your cleaner. If you are using tablets or powder, follow the package directions. If you are going the vinegar route and your manual allows it, pour 2 cups into the detergent dispenser or directly into the drum. Set the machine to its hottest, longest cycle. If yours has a Tub Clean or Self Clean setting, use it. Let it run.

This first cycle loosens the biofilm and dissolves detergent scale so the scrubbing steps actually accomplish something. If the machine is truly bad, pause the cycle halfway and let the hot water sit for an hour before letting it finish.

Step 2: Scrub the Rubber Door Seal

Front-loader owners, this is where most of your smell lives.

Pull back the folds of the rubber gasket around the door. The black buildup hiding underneath is the main event. Mix dish soap with warm water and work it into every fold with the toothbrush. Get right into the crevices. Wipe everything out with a damp microfibre cloth, then dry it fully with the second cloth. Leaving it damp just restarts the problem.

If you can’t tell whether you’re looking at mould or mildew on your clothes, the distinction matters for treatment, and the same visual cues apply inside the washer.

For staining that will not scrub out, a mould and mildew gel applied with gloves and left for a few hours will do what elbow grease cannot. It is not a quick-rinse product. Give it time to work.

Step 3: Clean the Detergent Drawer and the Slot It Slides Into

This is the step almost every guide skips, and it matters.

Pull the detergent drawer out completely. Most have a small release tab. You will probably find compartments you have never cleaned once, sticky with fabric softener residue and standing water. Soak the drawer in hot water and scrub it with the toothbrush.

Then reach into the empty slot the drawer came out of and wipe that down too. It is just as dirty, and you never see it once the drawer slides back in. Fabric softener is one of the worst offenders for buildup. That waxy coating gives bacteria exactly the surface they want.

Step 4: Clean the Drain Pump Filter

Your washer has a drain filter, usually behind a small door near the bottom front of the machine. It is almost certainly unpleasant in there.

Lay your old towel down first. Dirty water will come out when you open it, and the towel saves your floor. Turn the filter counterclockwise, pull it out, and clear out the hair, lint and sludge. Rinse it under hot water, scrub if needed, and put it back.

While you are down there, check the drain hose. If it is kinked or sitting in standing water, that is contributing to the smell. And if your washer smells like rotten eggs or sulphur specifically, the problem is often plumbing rather than the machine. A dried-out P-trap lets sewer gas rise up through the drain. Pouring water down the drain to refill the trap fixes it in about ten seconds.

How to Stop Your Washing Machine From Smelling Again

The deep clean is the easy part. Staying ahead of it is where people falter, but the routine takes about two minutes:

• Leave the door or lid open after every load. Airflow is the single biggest factor.
• Wipe the gasket dry after each wash, especially on a front-loader. Twenty seconds.
• Measure your detergent instead of eyeballing it. Excess detergent is one of the top causes of buildup.
• Run one hot wash per week, even if most loads are cold. Bacteria do not survive real heat.
• Clean the drain filter monthly. Set a phone reminder and forget about it otherwise.

Appliance technicians say the same thing every time: people assume washing machines clean themselves, but residue accumulates like plaque. The owners whose machines never smell are not buying special products. They are just doing these small things consistently.

When to Call a Repair Technician

If you have done all four steps and the smell persists, particularly a musty or sewage smell that will not quit, the problem may sit deeper than you can reach. Internal hoses, the outer tub and sealed drain components sometimes need a professional with the right tools. A service call also extends the life of the machine, so it is money spent once instead of a replacement bought years early.

Total cost of doing it yourself: a cleaner tablet and an hour of a Saturday. The towels smell like towels again. Go prop that washer door open.