Why Your Washing Machine Smells and How to Fix It

You open the washer expecting fresh linen and get a whiff of swamp instead. A machine built to clean clothes has no business smelling this bad, yet a stinky washing machine is one of the most common laundry complaints. It almost always comes down to what the drum traps between loads.

The smell itself is the clue. Musty means trapped moisture, rotten eggs mean sulfur bacteria or, if the smell fills the room, a gas leak, and a sewer stench means the drain rather than the drum, and each one takes a different fix.

The good news is that a smelly washer rarely means a repair. Most odors are mold, mildew, and bacteria feeding on trapped detergent and grime, and you can clear them with bleach, vinegar, or a cleaning tablet you probably already own.

What Does the Smell Tell You?

The smell names the cause: a musty odor means trapped moisture and mold, a rotten egg odor means sulfur bacteria or a gas leak, and a sewage stench means a drain or vent problem rather than a dirty drum. Most washing machine smells fall into those three groups, so a quick sniff test at the door, the drawer, and behind the machine will point you at the right fix before you start scrubbing.

Musty or Mildew Smell

This is the most common washer odor by far, and it comes from mold and mildew growing on trapped moisture. Front-loaders are especially prone to it because the door seals tightly and the horizontal drum and rubber gasket hold water and detergent film after every wash, creating the warm, damp conditions that breed mold and biofilm.

Timing is what makes it stick. According to the EPA, drying a wet surface within 24 to 48 hours usually stops mold from growing at all ⁽¹⁾, and a closed washer door keeps the gasket fold wet for much longer than that between loads. A cleaning cycle plus better drying habits usually clears it.

Rotten Egg Smell

If your laundry room smells like sulfur, bacteria is likely the culprit. Your washer is a dark, damp environment that collects dirt, lint, soap scum, and dead skin, and that mix is a steady food supply for the bacteria that give off sulfur gases as they break it down.

These microorganisms thrive in hard-to-reach places like the rubber door gasket, the lint trap, and the drum itself. In front-loading machines, small items like baby socks can get trapped behind the seal and start to rot, contributing to the funk.

Note: Natural gas and propane are odorless on their own, so utilities add an odorant called mercaptan that smells like rotten eggs specifically so a leak can be caught by nose, per the U.S. Pipeline and Hazardous Materials Safety Administration. If the smell is strong and fills the room rather than sitting inside the drum, do not go looking for the source. Leave the house and call your gas company from outside before assuming it is bacteria.

Sewage Smell

A sewage smell usually points to a plumbing issue rather than a dirty drum. It typically comes from an improperly installed P-trap, a dried-out trap, or a clogged vent pipe that lets sewer gas back up into the room instead of venting outside. That sewer gas is mostly hydrogen sulfide, which OSHA describes as both flammable and highly toxic, with a pungent rotten-egg odor even at low concentrations ⁽²⁾, so it is worth tracking down rather than masking.

Why Does a Washing Machine Smell?

A washing machine smells because trapped moisture and detergent residue feed mold and bacteria in the folds a wash cycle never rinses. During a wash, dirty water and suds splash above the water line and settle into the rubber seals and drum folds, where they never fully rinse away. A biofilm of soap scum, lint, and dead skin builds up in those spots.

High-efficiency machines make that buildup worse. According to ENERGY STAR, a certified front-load washer uses about 50% less water than a top-load agitator model, which is good news for the water bill. That also leaves less rinse water to carry detergent film out of the drum, so residue lingers exactly where the bacteria live.

That residue is food for mold and bacteria, and that is what you actually smell. Adding scented fabric softener won’t fix it; it only masks a rotting problem with a floral top note. To clear the odor for good, you have to both kill the bacteria and physically remove what they feed on.

How Do You Clean a Washing Machine With Bleach?

Pour 1 cup of chlorine bleach into an empty machine, run the hottest or Sanitize cycle, then wipe the drum, door glass, and gasket dry. Bleach kills mold and bacteria on contact, but it is not a degreaser, so it may not lift thick layers of soap scum on its own. Use this method when you need to disinfect the machine and knock out a heavy mildew odor.

Safety Warning: Never mix bleach with other cleaners, especially vinegar or ammonia. Bleach plus an acid like vinegar releases chlorine gas, and bleach plus ammonia makes chloramine gas; both irritate the eyes, nose, and throat, trigger coughing and breathing trouble, and at high levels can put fluid in the lungs ⁽³⁾. Open a window and run the vent before you begin, and never chase a vinegar clean with a bleach clean on the same day.

What You’ll Need

Gather these supplies before starting:

• Chlorine bleach
• Measuring cup
• Microfiber cloths
• Dish soap
• Hot water

1. Add the Bleach

Pour 1 cup of bleach directly into the bleach dispenser. If your machine is a top-loader without a dispenser, pour it straight into the empty drum.

2. Run a Hot Cycle

Check that the washing machine is completely empty, then run a “Sanitize” cycle, a “Tub Clean” cycle, or the longest regular wash available on the hottest water setting. Heat is doing half the work here, so a warm setting will not get you the same result.

3. Wipe the Interior

Once the cycle finishes, use a microfiber cloth to wipe down the interior. Focus on the areas that sit above the water line, the door glass, and the rubber door seal, since the cycle never reaches them properly.

4. Clean the Dispensers

Pull out the detergent and fabric softener drawers. Wash them in the sink with warm, soapy water to remove sticky buildup, and use an old toothbrush on the siphon cap where softener sludge collects. Dry them thoroughly before reinserting them.

How Do You Clean a Washing Machine With Vinegar?

Run white vinegar through an empty machine on the hottest setting, 4 cups poured into a filled top-load drum or 2 cups into a front-loader’s detergent dispenser, then wipe the seals by hand. Vinegar breaks down the mineral deposits and soap scum that bacteria feed on. It is not as strong a disinfectant as bleach, but it dissolves grime far better, which makes it the better choice for monthly maintenance between deeper sanitizing runs.

What You’ll Need

You will need the following items:

• White vinegar
• Measuring cup
• Microfiber cloths
• Dish soap

Top Load Washers

Follow these steps for standard top-loading machines:

1. Fill the Washer

Select the hottest water setting and the largest load size. Start the cycle and let the drum fill with water.

2. Add Vinegar and Pause

Once the machine is full and starts to agitate, open the lid or hit pause. Pour in 4 cups of white vinegar. Close the lid and let it agitate for about one minute to mix.

3. Soak the Drum

Pause the machine again and let the vinegar solution sit in the drum for at least 1 hour. That soak is what gives the acid time to break down scale and soap film rather than just rinsing past it.

4. Finish the Cycle

After the hour is up, restart the machine and let it complete the full wash and spin cycle.

5. Wipe and Dry

Use a cloth dipped in a vinegar-water solution to wipe down the agitator, the rim of the drum, and the inside of the lid, then leave the lid up so the drum dries out.

Front Load Washers

Front-loaders require a slightly different approach:

1. Start a Hot Cycle

Select the “Tub Clean” or heavy-duty hot water cycle. Pour 2 cups of white vinegar into the detergent dispenser.

2. Run the Wash

Let the machine run through the complete cycle. The vinegar will work its way through the internal plumbing and the drum.

3. Clean the Gasket

This is the step that matters most on a front-loader. Gently pull back the rubber door seal and use a cloth soaked in vinegar to wipe out the sludge, hair, and mildew trapped in the fold, working all the way around, including the bottom of the boot where water pools.

Does Baking Soda Clean a Washing Machine?

Baking soda cleans as a mild abrasive and odor absorber, so it works best paired with the vinegar method rather than used on its own. Keep the two apart until they are inside the machine, because premixing them in a cup just neutralizes both before they reach the grime.

1. Add Baking Soda

Pour 1/2 cup of baking soda directly into the drum (for both front and top loaders).

2. Add Vinegar

Pour 1 quart (4 cups) of vinegar into the drum (for top loaders) or the detergent dispenser (for front loaders).

3. Run a Hot Cycle

Run a full hot water cycle. The fizzing reaction helps loosen dirt, while the high heat flushes it away.

Do Washing Machine Cleaner Tablets Work?

Washing machine cleaner tablets work well on odor and residue, though they do not sanitize as heavily as bleach does. They come pre-measured and are formulated to break down buildup without damaging rubber hoses or voiding a warranty.

Note: If your machine already smells musty, one clean will not reset it. According to LG, you should run the Tub Clean cycle once a week for 3 weeks to clear an established odor, then drop back to a monthly clean ⁽⁴⁾.

Consider these top-rated options:

• Affresh Tablets
• Affresh Washing Machine Wipes
• Tide Washing Machine Cleaner with Oxi
• Eco-Gals Eco Swirlz Washing Machine Cleaner
• Lemi Shine Washing Machine Cleaner and Cleaning Wipes

1. Insert the Tablet

Place one tablet directly into the empty washer drum. Do not put it in the dispenser drawer unless the package specifically instructs you to.

2. Run a Hot Cycle

Select a “Clean Washer” cycle or a normal hot water cycle. The heat is necessary to dissolve the tablet fully, so skip the cold or eco setting here.

3. Wipe Residue

Once finished, wipe away any leftover residue on the gasket or door glass with a commercial wipe or a damp cloth, then leave the door open until the drum is dry.

How Do You Stop a Washer From Smelling?

A washer stops smelling once the drum stays dry and the residue stays low: leave the door open after every load, wipe the gasket, measure HE detergent, and clean the machine monthly. Maintenance is far easier than a deep clean, so build these habits into the laundry routine:

• Clean your machine monthly using one of the methods above.
• Leave the washer door or lid open after every load to let the drum dry out completely.
• Use low-suds “High Efficiency” (HE) detergent in front-loaders and measure it; too much detergent, or the wrong type, leaves residue that feeds the odor-causing biofilm.
• Clean the drain pump filter (behind the small access door at the bottom front of most front-loaders) on a monthly schedule, which is what both Whirlpool and LG tell owners to do; it catches lint, coins, buttons, and stray socks before they reach the pump and start to rot.
• Remove wet clothes immediately; never let them sit overnight.
• Run a hot water wash for your towels or whites periodically to flush the system.
• Wipe the gasket fold dry with an old towel after the last load of the day, and pull out any coins, hair ties, or socks you find in it.

The room matters as much as the machine. The EPA recommends keeping indoor humidity under 60%, and ideally between 30% and 50%, because damp air lets mold regrow on the surfaces you just cleaned, so run the exhaust fan or a dehumidifier if your laundry room stays muggy.

Troubleshoot Sewage Smells

If your machine is clean but the room smells like a sewer, the problem is in the plumbing, and there are three places to check before you call anyone.

The Drain Hose

Pull the washer away from the wall and smell the drain hose. If the odor is coming from there, bacteria might be growing inside the corrugated tubing. You may need to replace the hose or use a long brush to clean it out.

The P-Trap

Pour a gallon of water down the washing machine drain pipe. If the P-trap (the U-shaped pipe) has dried out from lack of use, the water will seal it again and block sewer gas from entering the room. A trap in a rarely-used laundry room can dry out, so this is worth trying first.

The Vent Pipe

Your plumbing needs a vent pipe (usually on the roof) to allow air into the system. If this is clogged with leaves or a bird’s nest, the water won’t drain smoothly, and smells can back up. If you aren’t comfortable climbing on the roof, call a pro.

When to Call a Plumber

If you have verified the machine is clean, filled the P-trap, and still smell sewage, it’s time to call a plumber. You may have a blockage deep in the line or a vent issue that requires professional tools to clear.

FAQs

Eliminate the Stink

A smelly washer is rarely permanent, and the smell itself tells you where to aim. A musty or mildew note means trapped moisture, so a hot cleaning cycle, an open door between loads, and a dry gasket clear it. A rotten egg scent points to sulfur bacteria living in the drum and seals, which a bleach sanitize knocks out (rule out a gas leak first if the smell fills the room). A sewage stench is a plumbing problem rather than a dirty drum, so refill the P-trap and check the vent before you scrub anything. Match the fix to the smell, keep the door open and the gasket dry between loads, and the drum goes back to smelling like nothing at all.