Why Does My Washing Machine Smell Like Rotten Eggs?

If your washing machine smells like rotten eggs, the odor is usually coming from bacteria, trapped water, or sewer gas—not the machine itself going bad.

This smell can get worse when the washer runs or right after a cycle finishes.

Here’s what typically causes it and what you can do about it.

Why a Washing Machine Smells Like Rotten Eggs

That sulfur smell usually comes from one of these issues:

• Bacteria buildup inside the washer
• Standing water in the drain or hose
• Sewer gas backing up through the drain
• Mold or mildew trapped in hidden areas

The good news is most of these are fixable without replacing anything.

What to Check First

Start simple before assuming a major problem.

• Run an empty hot-water cycle
• Smell the washer during and after the cycle
• Check if the smell is stronger near the drain pipe

This helps narrow down whether the issue is inside the washer or coming from the drain.

Common Causes and Fixes

1) Bacteria Buildup Inside the Washer

Detergent residue, fabric softener, and moisture can create bacteria that smells like sulfur.

Fix:

• Run a hot cycle with white vinegar or a washer cleaner
• Follow with a second hot cycle using baking soda
• Leave the door or lid open after washing to dry the tub

This is the most common cause.

2) Dirty or Clogged Drain Hose

Water can sit in the drain hose and grow bacteria.

Fix:

• Pull the washer out carefully
• Check the drain hose for kinks or sagging
• Flush the hose with hot water if possible

If water can’t drain freely, smells will come back.

3) Sewer Gas Coming From the Drain

If the smell is strongest near the wall drain, sewer gas may be escaping.

This happens when:

• The drain trap dries out
• The washer isn’t used often
• There’s a plumbing vent issue

Fix:

• Pour water into the drain to refill the trap
• Run the washer at least once a week

If the smell keeps returning, a plumber may need to check the venting.

4) Mold or Mildew in Hidden Areas

Smells can hide in:

• Rubber door gasket (front-loaders)
• Detergent drawer
• Under the washer lid

Fix:

• Wipe seals and gaskets with vinegar
• Remove and clean the detergent tray
• Dry all areas thoroughly

When It’s Probably Not DIY

Call a professional if:

• The smell is strong throughout the house
• Sewer odors persist after cleaning
• You suspect a plumbing vent or drain issue

Those problems are usually outside the washer itself.

Quick Recap

If your washing machine smells like rotten eggs, the most common causes are:

• Bacteria buildup
• Standing water in the drain system
• Sewer gas from a dry or blocked trap

Regular cleaning and proper drainage usually solve the problem.