Why Does a Washing Machine Smell Musty?

If the washer smells musty but the clothes come out clean, the odor is living in the machine rather than the laundry. That distinction matters, because adding more detergent or fragrance will not remove it.

Where the Smell Comes From

Modern washers use less water than older models. Less water means less flushing of the spaces you never see: the door gasket on a front loader, the detergent dispenser drawer, the fabric softener cup, the drain pump filter and the outer tub.

Residue from detergent, softener and lint collects in those spaces and stays moist between cycles. Microorganisms grow in that film, and the musty smell is the result. Two habits make it worse:

• Cold, short cycles only. They clean clothes adequately but do not flush residue from the machine.
• Closing the door or lid right after a wash. Trapped moisture keeps the interior damp for hours.

Clean the Parts You Can Reach

Work through these in order, using the machine's manual for your model.

1. Door gasket. Wipe the inside of the rubber seal with a damp cloth, then dry it. Grit and hair collect in the lower fold.
2. Detergent drawer. Remove it, rinse it in warm water and clean the housing behind it with a small brush.
3. Drain pump filter. Most front loaders have one behind a small panel at the bottom front. Place a towel down, because water drains out.
4. Drum and tub. Run a hot, empty maintenance cycle with a washing machine cleaner, or according to the manual. Some manufacturers specify a specific cleaner and cycle.
5. Lint filter on a top loader, if the model has one.

Do not pour bleach into a machine unless the manual allows it, and never mix cleaning products.

Change the Habits That Feed It

• Leave the door or lid open between loads so the interior dries.

Use the dose on the detergent label. More detergent leaves more residue, especially in soft water.

Reduce fabric softener use if the machine is prone to buildup. Softener is a common contributor to the film.

Run a warm or hot cycle occasionally rather than only cold washes.

Wipe the gasket dry every few weeks, and remove the load promptly when the cycle ends.

When It Is Not Just Maintenance

Persistent odor after cleaning, standing water in the drum, slow draining or a smell that returns within days points to a drainage or component issue. In that case, a technician is the right next step rather than another cleaning cycle.

If the clothes themselves smell sour after washing, that is a related but different problem. See why do clothes smell sour after washing and why is my washer making too many suds.