Washing Machine Smells Like Rotten Eggs? How to Fix It

1. Clean the door gasket (front-loaders)

The rubber boot around a front-loader door is the #1 source of mildew smell. Peel it back gently and wipe every fold with a cloth dampened in warm water and a little dish soap or diluted bleach (1:10). Pull out coins, hair, and lint. Dry the fold, then leave the door cracked open between loads so the gasket can air out.

2. Clean the detergent drawer

Slide the dispenser drawer all the way out (most have a release tab in the softener compartment). Soak it in hot water and scrub the underside and the drawer cavity with an old toothbrush. Sour, slimy buildup here feeds the same mildew that lives on the gasket.

3. Run a maintenance cycle

Run the machine's Tub Clean or Clean Washer cycle on the hottest setting. If there's no dedicated cycle, use the longest hot wash. Options in order of strength:

• Affresh or a washer-cleaner tablet in the empty drum — the easiest routine option.
• 2 cups of white vinegar in the drum plus ½ cup of baking soda in the detergent drawer — good monthly maintenance.
• 1 cup of bleach in the bleach dispenser on a hot cycle for stubborn mildew. Run a second hot rinse afterward before washing clothes.

4. Clear the drain pump filter

Rotten-egg or sulfur smells often trace to a pump filter clogged with lint, hair, and standing gray water. On most front-loaders it's behind a small panel on the lower front of the machine. Put a shallow pan and towels under it — several cups of water will come out. Rinse the filter, clear any debris in the housing, and reinstall.

5. Check the standpipe and P-trap

A true sewer smell — sulfur, sharp, worst right after a load drains — usually isn't the washer at all. It's a dry P-trap on the laundry standpipe letting sewer gas back into the room, or a standpipe without a proper vent. Pour a quart of water down the standpipe to refill the trap; if the smell returns within a day or two, the drain needs a plumber, not a repair on the washer.

6. Change your laundry habits

High-efficiency (HE) washers use very little water, so regular detergent and heavy doses of any soap leave residue that goes rancid. Use HE-labeled detergent, measure by the manufacturer's line (not the cap), skip fabric softener in the drum, and leave the door and drawer open between loads. Move wet laundry to the dryer promptly.

When to call a pro

Call for service if the smell comes back within a week of a thorough clean, if you see standing water in the drum between loads, if the pump filter is missing or won't seat, or if the odor is sewer-sharp and refilling the P-trap doesn't help. Persistent smells often mean a failed sump seal, a cracked bellows on a front-loader, or a drain hose looped incorrectly behind the machine.

Knapp's Service & Appliance Repair diagnoses and repairs washing machines throughout Portland and the surrounding Oregon communities we cover. Submit a service request with the make, model, and a note about the smell and we'll follow up.