Why mold grows in washers and where to look
Mold grows in your washer because the machine holds moisture, detergent residue, and fabric lint in dark spaces—exactly what mold needs to thrive. The most common spots are the rubber gasket (the seal around the door on front-loaders), the detergent dispenser drawer, the drum itself, and the drain hose. You'll notice a musty smell when you open the door, or see black or pink spots on the rubber seal and inside the drum.
Front-load washers are more prone to mold than top-loaders because water sits longer in the sealed drum and gasket. Top-loaders drain faster, but mold can still grow under the agitator and in the drain pump filter. If you've noticed the smell but haven't seen visible growth yet, mold is likely already present in the drain hose or pump—places you can't see from the outside.
Key Takeaways
- The rubber gasket on front-loaders and the drain hose are the most common mold hideouts; check both before you start cleaning.
- A hot water cycle with white vinegar or a commercial washer cleaner will kill mold in the drum, but you must also clean the gasket and dispenser by hand.
- After each wash, leave the door open for at least an hour so moisture evaporates and mold cannot establish itself.
- If the smell returns within a few weeks, the drain hose or pump filter likely needs replacement—a job best left to a technician.
Cleaning the drum with vinegar or washer cleaner
Start by running a hot water cycle with white vinegar. Pour two cups of white vinegar directly into the drum (not the detergent dispenser), then run the hottest, longest cycle your machine offers—usually a heavy-duty or sanitize setting. The heat and acidity kill mold spores and break down the buildup that feeds mold growth. Do not add clothes; run the machine empty.
If vinegar doesn't work or you prefer a commercial product, use a washer-specific cleaner like Affresh, Clorox Washer Cleaner, or Tide Washing Machine Cleaner. Follow the package instructions exactly—most require you to place the tablet or pour the liquid into the drum, then run a hot cycle. These products are formulated to dissolve in the machine's plumbing and kill mold more aggressively than vinegar. Run the cycle twice if the smell is strong.
After the cycle finishes, wipe down the inside of the drum with a clean cloth to remove any remaining debris. Leave the door open for at least two hours so the drum dries completely.
Cleaning the rubber gasket on front-loaders
The rubber seal around the door is where mold most visibly grows. Pull the gasket gently away from the drum to expose the crevice underneath—this is where water and lint collect. Use a damp cloth or an old toothbrush to scrub along the entire seal, paying special attention to the bottom where water pools. For stubborn mold, soak the cloth in white vinegar or a 1:1 mixture of bleach and water, then scrub again.
If the gasket is heavily damaged, cracked, or the mold keeps returning to the same spot, the seal may need replacement. This is a part you can order online for most machines (search your model number plus "gasket"), but installation varies—some snap in place, others require tools. If you're not comfortable removing the old gasket and installing the new one, a technician can do it in under an hour.
Cleaning the detergent dispenser drawer
Remove the dispenser drawer by pressing the release button or lever (usually in the center of the drawer). Rinse it under hot running water to flush out detergent buildup and mold. Use an old toothbrush to scrub the compartments, especially the corners where liquid detergent pools. Soak the drawer in hot water with a cup of white vinegar for 15 minutes if mold is visible, then scrub and rinse again.
While the drawer is out, look into the slot where it sits. Wipe the inside of that opening with a damp cloth or vinegar-soaked cloth to remove mold growing in the cavity. Dry the drawer completely before sliding it back in.
Checking and cleaning the drain hose
The drain hose is a common mold hideout because water sits in it between cycles. If the musty smell persists after you've cleaned the drum and gasket, the hose is likely the culprit. Locate the hose at the back of the machine—it's usually a ribbed plastic tube running from the drum to the wall drain or standpipe.
If you're comfortable doing it, disconnect the hose at both ends (have a bucket ready to catch water) and flush it with hot water mixed with vinegar. You can also use a plumbing snake or a straightened wire coat hanger to break up blockages inside the hose. Reconnect it securely and run a test cycle to make sure water drains properly.
If the hose is cracked, kinked, or the smell doesn't improve after flushing, the hose should be replaced. This is a straightforward part swap, but if you're not confident working behind the machine, call a technician. A new drain hose costs $15 to $40 in parts, plus labor if someone installs it.
Preventing mold from coming back
The most important step is leaving the door open after every wash. Mold cannot grow without moisture, and an open door lets the drum dry within an hour. If you have a front-loader, prop the door open with a small object or leave it cracked—don't close it when ready after the cycle ends. This single habit prevents 90 percent of mold problems.
Use the correct amount of detergent. Excess detergent leaves residue that feeds mold growth. High-efficiency (HE) machines use less water, so they need less soap—follow the bottle's guidance for your machine type. Run a cleaning cycle once a month using vinegar or a commercial cleaner, even if you don't smell mold yet. This keeps spores from building up.
If your machine has a drain pump filter (most front-loaders do), clean it every three months. The filter is usually accessed from a small door at the bottom front of the machine. Unscrew the filter, rinse it under hot water, and wipe the cavity behind it with a damp cloth. Reinstall it and run a test cycle to confirm water drains.
When to call a technician
If the smell returns within two to three weeks after a thorough cleaning, or if you see mold growing back on the gasket when ready, the problem is likely inside the machine where you can't reach—usually the drain pump, the tub seal, or the hose. A technician can inspect these parts, replace them if needed, and confirm the machine is draining properly. This typically costs $150 to $300 in service and parts, depending on what needs replacing.
Do not ignore a persistent mold smell. Mold spores can irritate your lungs and skin, especially if you have asthma or allergies. If cleaning doesn't work, professional service is worth the cost. Some machines with severe internal mold damage may not be worth repairing—your technician can advise whether replacement makes sense.
Frequently Asked Questions
Can I use bleach to clean mold in my washer?
Bleach kills mold, but it can damage rubber gaskets and seals over time, and it's harsh on the machine's internal parts. White vinegar or a commercial washer cleaner is safer and equally effective. If you use bleach, dilute it to 1 part bleach to 10 parts water, explore it only to visible mold on the gasket, and rinse thoroughly.
Is it safe to wash clothes in a moldy washer?
Clothes washed in a moldy machine will smell musty and may develop mold themselves, especially if they sit damp in the machine. Mold spores can also transfer to your skin. Clean the machine before washing clothes again. If clothes already smell moldy, wash them separately in hot water with vinegar or a commercial odor remover.
Why does my washer smell moldy even though I leave the door open?
If the door is open but the smell persists, the mold is likely in the drain hose, pump filter, or inside the tub where air doesn't reach. Run a hot vinegar cycle and clean the pump filter if your machine has one. If the smell still doesn't improve, the drain hose may need replacement or the pump itself may be blocked.
How often should I run a cleaning cycle?
Run a cleaning cycle once a month as preventive maintenance, or when ready if you notice a musty smell. If you use your washer heavily (more than once a day) or live in a humid climate, clean it every two weeks. The effort takes 30 minutes and prevents mold from establishing itself.
Can mold damage my washing machine permanently?
Mold itself doesn't damage the machine's mechanical parts, but the moisture and buildup that allow mold to grow can corrode the drum, seals, and pump over time. Catching and cleaning mold early prevents this damage. If mold has been present for months, internal rust or seal failure may require professional repair.