Why Does My Laundry Room Smell Like Sewage?

If you’ve ever discovered that your laundry room smells like sewage, you probably thought there was a serious problem with your plumbing. When you have an odor like that in any room of your house, you’ll want to fix it quickly to prevent the smell from permeating your entire home.

Why Does My Laundry Room Smell Like Sewage

So, what can make your laundry room smell like sewage? If you guessed that the smell was coming from your plumbing, you might be right.

Unfortunately, leaky plumbing isn’t the only thing that can make your laundry room stink. The odor could also come from mold or a dirty washer.

What Causes A Sewer Smell In Your Laundry Room?

If your laundry room smells like sewer gas, you probably have a problem with your plumbing. Some of these issues include a clogged or broken pipe or a dry p-trap in your laundry sink.

If your plumbing is okay, the odor may come from mold instead. Let’s take a closer look at some of the most common reasons for a sewage smell in your laundry room.

1. Broken Sewer Pipes

If your laundry room smells like sewer gas, you might have a broken pipe. This pipe can either be in your home or the main sewer line that connects to your house.

In either instance, broken pipes can allow sewer gases to leak into your home and cause a nasty odor. This problem should not be ignored, as sewer gas is highly flammable and can cause significant health issues.

2. Mold And Bacteria

Another possible cause of sewage odors in your laundry room is mold and bacteria growth. If the pipe that goes to your washing machine leaks or the drains get clogged, water can pool.

Mold and bacteria thrive in dark, wet environments and will grow out of control in stagnant water.

3. Dirty Washing Machine

A dirty washing machine can lead to a sewage-type smell in your laundry room. If you never run a clean cycle on your appliance, the dirt and odor from the clothing you wash can build up in the drum of your machine.

If you regularly leave wet clothes in your washer or dryer for more than a day, it can also encourage the growth of mold and bacteria that can make the room smell bad.

4. Poor Air Flow

If your laundry room isn’t ventilated properly, it can cause humidity to build up. This humidity can eventually make the room smell bad, and it will undoubtedly exacerbate any other problems you might have.

5. Dry P-Traps

Your washer and laundry sink both have p-traps that are filled with water. This water creates a seal that keeps sewer gases from entering your home.

Most people use their laundry rooms frequently enough to prevent this problem, but if your washer has been on the fritz, you don’t use your laundry sink, or you’ve been out of town for an extended period, one of your p-traps could dry out and allow sewer gas to leak into your home.

How To Fix The Sewer Smell In Your Laundry Room

The first step in removing the sewer smell from your laundry room is pinpointing the problem.

cleaning a washing machine

We’ve talked about the causes of a sewage smell in the laundry room; now, let’s look at how you can remedy each issue and clear up the odor.

1. Clean Your Washing Machine

If your laundry room stinks, clean your washer to see if the smell disappears.

Follow these simple steps to get your washing machine sparkling clean and smelling fresh:

  • Select the clean cycle on your washer. If your appliance doesn’t have this setting, you can choose the highest, hottest wash cycle instead.
  • Add 3 to 4 cups of white distilled vinegar as the drum fills with water.
  • After a few minutes of agitation, stop the cycle and let the vinegar soak in.
  • Add ½ cup of baking soda to your machine, then start the cycle again.
  • Let the agitator run for a few minutes, then stop it for about an hour to allow the solution to soak.
  • After soaking, allow the cycle to finish as usual.

You should also check the rubber seal on the door and the door itself for any mold or bacteria. Spray the seal with vinegar and scrub with a brush to remove any dirt.

2. Clean The Pipes

If cleaning your washing machine didn’t get rid of the smell, the next thing you can try is cleaning out your pipes.

All you need to do is remove the cover on the drain in your floor and pour a cup of baking soda, followed by a cup of vinegar, to remove any dirt and debris that may be clogging it.

3. Run Water In Your Laundry Sink

If you have a dry p-trap, you’ll need to run water in your laundry sink to reactivate the seal. Both solutions above focus on your washing machine as the source of the odor, so you’ll already have run water through those pipes.

If a dry trap is causing your laundry room to smell like sewage, the smell should improve in 30 minutes to an hour after running water.

4. Check The Room For Mold

If your washing machine and pipes are clean and you don’t have a dry p-trap, the next thing you should do is look for mold in your laundry room.

Check anywhere that could have a leak, like the pipes that go to your sink and washer. Any amount of standing water will encourage mold spores to grow. If the pipes are clear, check the corners of the laundry closet.

If your laundry room is in the basement, look for signs of water damage on the floor or walls that could indicate a crack in your foundation.

Mold is a major health hazard, so if you find some growing in your laundry room, you’ll need to clean it up immediately. Mold spores move through the air when disturbed, so make sure you wear protective gear like safety glasses, a mask, and gloves to limit contact with the spores.

You can kill mold naturally by spraying vinegar on the moldy surface. Let it sit for about an hour, then wipe the surface clean and allow it to dry. 

5. Check For Broken Pipes

If none of the solutions above eliminate the smell of sewage in your laundry room, you probably have a broken sewer pipe. If you find a broken pipe, don’t try to handle this problem yourself.

Sewer gas is highly flammable and can be hazardous to your health, so you’ll need to call a licensed plumber to fix the pipe immediately.

6. Improve Ventilation

Opening a window for ventilation

No matter what’s causing the sewage smell in your laundry room, improving the ventilation in the area will help it dissipate quickly. Open your windows and screen doors and turn on the vent and ceiling fans.

If you have an air purifier, put it in the room and add a few drops of essential oil to help mitigate the odor. You can also set a bowl of baking soda on top of your dryer to absorb some of the smell. 


Can sewer gas come up through the washing machine?

Yes, sewer gas can come up through the washing machine if the p-trap dries out. To fix this problem, just pour some hot, soapy water down the standing drain in your floor. In rare instances, the p-trap may be faulty. In this instance, you’ll need to call a plumber to replace it.

Why does my house smell like sewage when I do laundry?

The most common causes of sewage smell when doing laundry include a dirty washing machine, clogged pipes, dry p-traps, and mold and mildew.

Can you pour bleach down the washing machine drain?

Although it may seem like a simple solution to get rid of smelly plumbing, you should never pour bleach down your washing machine drain. Bleach releases toxic fumes on contact with other substances, including certain laundry detergents and cleaning agents. If you pour bleach into your drain after using any of these products, you could release toxins like chlorine gas into your home and cause more significant problems than a bad smell in the room.

Guides For Removing Other Smells;


If you smell sewage in your laundry room, you’ll need to locate the source of the odor. Some of the most common causes of sewer-type smells in the laundry room include:

  • Mold and bacteria
  • A dirty washing machine
  • Dry p-traps
  • Poor ventilation
  • Broken sewer pipes
Shauna Stone