Washing Machine Drain Smells Like Sewage: Causes and Fixes

When your washing machine drain smells like sewage, the result can be anything from a mild nuisance to a major health hazard. The good news is that there are some things you can do to fix the issue and prevent it from happening again. Here’s everything you need to know.

A dry P-trap is the most common reason your washing machine drain might smell like sewage. The P-trap is the U-shaped pipe designed to prevent sewer gasses from entering your home. The water in this pipe acts as a plug between sewer gases and your washer.

This article explains why your washing machine drain might smell like sewage and provides some tips on fixing the issue. Read on to get rid of the sewage smell from your washing machine drain!

Why Your Washing Machine Drain Smells Like Sewage

Here’s the thing:

Your washing machine drain is connected to your home sewer system. As you probably know, the sewer system is full of all kinds of nasty things, including sewage. So, it’s not surprising that your washing machine drain might smell like sewage from time to time.

There are a few different reasons why this might happen:

The P-Trap Is Dry

The most common reason your washing machine drain smells like sewage is that the P-trap is dry.

The P-trap is a U-shaped pipe that’s part of all drain lines. It’s designed to trap water between the washer and the drain pipe, so the gasses don’t leak. If the P-trap is dry, it can allow sewer gases to escape and cause a nasty smell.

I know the question running through your mind: how come the P-trap is dry in the first place?

Well, there are a few different reasons:

The most common reason is that you haven’t used your washing machine in a while and the water in the P-trap has evaporated.

Another possibility is that your washing machine uses a tray to catch leakages. This design is usually used in laundry rooms on upper floors to prevent water damage to the structure. And because you’ll rarely have leaks with a washing machine, the P-trap in this drain line can dry up, allowing sewer gases into the home.

Bacteria Build-up in the Washing Machine Drain

Another reason your washing machine drain might smell like sewage is because of bacteria build-up.

Bacteria are present in all drains but can build up to unhealthy levels if the drain isn’t used frequently. Washing machine drains are particularly prone to this problem because they’re not used as often as other drains in the home, such as kitchen or bathroom sinks.

When bacteria build up in the drain, they can release a foul odor. This usually happens when the decomposed organic matter from the bacteria finds its way to your washing machine.

Using Too Much Detergent

Using too much detergent when you wash your clothes can cause a build-up of soap scum in your washing machine. And this soap scum can provide a food source for bacteria, which can lead to a foul odor.

I know this might not be the root cause of your particular problem. But it’s still a good idea to use the correct amount of detergent when you wash your clothes. Not only will this help prevent a smelly washing machine, but it will also save you money in the long run.

Not Cleaning Your Drain Hose Regularly

If you don’t clean your washing machine’s drain hose regularly, it can cause a build-up of lint and other debris. And this debris can provide a food source for bacteria, leading to a foul odor.

So, how often should you clean your drain hose?

Well, that depends on how often you use your washing machine. If you use it frequently, you should clean the drain hose at least once a month. But if you only use it occasionally, you can probably get away with washing it every few months.

Plumbing Issues

In some cases, the problem might not be with your washing machine at all. Instead, it might be a plumbing issue.

For example, if your home has a septic tank, it’s possible that the tank is full and needs to be emptied. Also, there could be a blockage in the sewer line that’s causing sewage to back up into your washing machine drain.

If you suspect that the problem is with your home plumbing, it’s best to call a plumber and have them take a look.

How to Fix a Smelly Washing Machine Drain

Now that you know some of the reasons why your washing machine drain might smell like sewage, it’s time to talk about how to fix the problem.

Here are a few different things you can do:

1. Clean Your Washing Machine Drain Hose

If you haven’t done so already, start by cleaning your washing machine’s drain hose. This will remove any lint or debris that might provide a food source for bacteria.

To clean the drain hose, disconnect it from your washing machine and remove any clamps holding it in place. Once the hose is free, flush it out with hot water. You can also use a stiff brush to scrub away any stubborn build-up.

Once you’ve cleaned the hose, reattach it to your washing machine and turn on the water. Let the water run for a few minutes to flush out any remaining debris.

2. Clean Your Washing Machine Drain Pump Filter

If your washing machine has a drain pump filter, make sure to clean it regularly. A build-up of lint or debris in the filter can cause a foul odor.

To clean the filter, disconnect your washing machine from the power source and locate the filter. The location of the filter will vary depending on your washing machine model, so consult your owner’s manual if you’re unsure where it is.

Once you’ve located the filter, remove it and rinse it off with hot water. If there’s a lot of build-up, you can soak the filter in a vinegar solution for a few hours before rinsing it off.

Once the filter is clean, reattach it to your washing machine and turn on the power.

3. Pour Vinegar Down Your Drain

Vinegar is a natural disinfectant that can kill bacteria. So, if your washing machine drain smells like sewage, pour a cup of vinegar down the drain and let it sit for an hour or two.

After the time has elapsed, flush the drain with hot water. The vinegar smell should be gone, and the drains should be bacteria-free. I also found that using powder detergent with vinegar helps remove any lingering odors.

If vinegar doesn’t do the trick, you can try using a commercial drain cleaner. Just be sure to use one that’s safe for plumbing and carefully follow the instructions on the bottle.

4. Check Your Home Plumbing

If you’ve tried all of the above and your washing machine drain still smells like sewage, there’s a good chance the problem is with your home plumbing.

For example, if you have a septic tank, it might be full and need to be emptied. Also, there could be a blockage in the sewer line that’s causing sewage to back up into your washing machine drain.

If you suspect that the problem is with your home plumbing, it’s best to call a plumber and have them take a look.

5. Clean the Detergent Tray

If your washing machine has a detergent tray, make sure to clean it regularly. Over time, detergent and fabric softener can build up in the tray and cause a foul odor.

To clean the tray, remove it from your washing machine and rinse it off with hot water. If there’s a lot of build-up, you can soak the tray in a vinegar solution for a few hours before rinsing it off.

Once the tray is clean, reattach it to your washing machine.

6. Scrub the Drum

Many people forget to clean the washing machine drum, but it’s an important step in keeping your machine smelling fresh.

To clean the drum, fill your washing machine with hot water and add a cup of vinegar. Let the machine run for a few minutes, then turn it off and let the water sit for an hour.

After the time has elapsed, scrub the drum with a sponge or brush. If there’s a lot of build-up, you can soak the drum in a vinegar solution for a few hours before scrubbing it.

Once the drum is clean, drain the water and run the machine on an empty cycle to rinse any remaining debris.

7. Create a Ventilation System in the Laundry Room

If your washing machine is in a confined space, such as a laundry closet, create a ventilation system to prevent odors from building up.

For example, you can install an exhaust fan in the laundry closet or drill holes in the bottom of the door to allow air to circulate.

You can also try leaving the door to the laundry room open when the washing machine is in use.

By following these tips, you should be able to get rid of that foul sewage smell coming from your washing machine drain. But if the problem persists, it’s best to call a plumber and have them take a look.

Here is a YouTube video that shows how to clean a smelly washer:

How to Avoid Sewage Smell in Washing Machine Drain

Now that you know how to get rid of the sewage smell in your washing machine drain, let’s talk about how to prevent it from happening in the first place.

Use Hot Water When Possible

One of the main causes of a sewage smell is bacteria build-up. And one of the best ways to prevent bacteria build-up is to use hot water when possible. So, if your washing machine has a hot water setting, use it. The hotter the water, the less likely bacteria are to survive.

Don’t Overdo the Soap

Using too much soap can leave a residue in your washing machine that will eventually lead to bacteria build-up.

So, only use as much soap as you need. If you’re unsure how much to use, consult your washing machine manual or the manufacturer’s website. However, a general rule of thumb is to use about 1/2 cup of soap for a regular load.

Clean the Machine Regularly

To prevent a sewage smell, it’s important to keep a regular washing machine cleaning schedule. This includes both the exterior and interior of the machine. For the exterior, all you have to do is wipe it clean with a damp cloth. And for the interior, be sure to clean the detergent tray and scrub the drum every month.

Inspect the Drain Hose and P-trap Regularly

Another way of preventing a sewage smell is to inspect the drain hose and P-trap regularly. These are two of the most common places where odors can build up.

At least once a month, disconnect the drain hose from the back of your washing machine and check it for any blockages. If you find any, clear them out and then reattach the hose.

Also, take a look at the P-trap under your sink. This “U” shaped pipe is responsible for trapping any water that goes down the drain. If this becomes clogged, it can cause sewage smells.

Over to You

By following these tips, you can prevent a sewage smell from happening in the first place. But if the problem does arise, now you know how to fix it.

You want to start with trying to clean the machine itself as best as possible. If that does not work, you want to look at the hose and see if anything is clogging it and causing the smell. If you still cannot figure it out, it may be time to call a professional.

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