Here's Why Your Washing Machine Smells Like Sewage (and What You Can Do)
You should be able to breathe the fresh air in your laundry room
Highlights
Several components in your laundry’s plumbing could be releasing sewer gasses.
Sewage smells usually indicate a problem different than mildew or rotten egg odors.
Dried P-Traps and clogged pipes are the most common culprits of sewer smell.
Seek the help of the pros when addressing plumbing and sewage issues in your home.
Have you opened your washing machine, expecting the fresh scent of clean laundry, only to be hit by a foul sewer odor? You're not alone. Many have experienced the perplexing issue of their washing machine giving off some seriously unpleasant smells. There are a few possible reasons your washing machine smells like sewage, and fortunately, there are also some fixes.
Washing Machine Plumbing Components
Before we explore the reasons behind the sewage-like smell in your washing machine, let's first understand the key plumbing components involved and their purposes in your laundry room.
Drain Pipe
The drain pipe is the flexible, usually gray colored hose that attaches your washing machine to your home’s plumbing. Its primary purpose is to carry wastewater away from the machine after the wash and rinse cycles and transfer the dirty water to your home’s sewage plumbing pipes.
P-Trap
This distinctive U-shaped plumbing component is installed beneath the stand pipe. The purpose of the P-Trap is to prevent sewer gases from entering the home. It does this by trapping a water seal, creating a water barrier that blocks sewer gases from escaping through the drain.
Stand Pipe
A standpipe is a vertical pipe—usually a few feet tall—that connects the drain pipe to the home’s plumbing through the P-trap. This pipe provides a dedicated outlet for the washer's wastewater, preventing overflows, leaks, and backflow. Properly installed, the stand pipe ensures efficient water drainage during your laundry cycles.
Vent Pipe
A washing machine vent pipe is typically located behind the machine and extends vertically through the roof. This pipe allows air to enter the plumbing system, creating a smooth flow of wastewater drainage from the washer and preventing siphoning, traps, sewer odors, and blockages.
5 Reasons Your Washing Machine Smells Like Sewage
Now that we have a basic understanding of the plumbing components, let's explore the five main reasons why your washing machine might be giving off a sewage-like smell.
1. Problem With the P-Trap
The P-Trap's water barrier can evaporate over time or be ineffective if the component isn’t installed correctly. When this happens, sewer gases can creep back into your laundry area.
2. Clogged Drain Pipe
A clogged drain pipe can lead to stagnant water in the washing machine's plumbing, which can develop a foul smell. This blockage may be caused by lint, debris, or soap scum accumulation.
3. Clogged Vent Pipe
Obstructions or clogs sometimes occur in the vent pipe. When this happens, it disrupts the proper flow of water and can result in sewage odors leaking back into your washer.
4. Too Much Detergent or Fabric Softener
Detergent can build up in your washing machine over time, and fabric softener is very hard on your system. When these two products sit in your washing machine or its drain pipes for a long time, they get difficult to break down. They also begin to harbor bacteria that can quickly cause a less-than-pleasant smell in your washing machine.
5. You Haven’t Run a Cleaning Cycle in a While
If you haven’t run a cleaning cycle in a few months, or if you don’t remember ever running one, that could explain the sewage smell. Cleaning cycles are important for, well, cleaning your washing machine and keeping foul smells at bay. Try to run a cleaning cycle once a month or every 30 washes, whichever comes first.
What to Do When Your Washing Machine Smells Like Sewage
Now that we've identified the potential culprits, let's discuss what you can do to eliminate the unpleasant sewer odor from your washing machine.
1. Clean Your Washing Machine
Regularly cleaning your washing machine is essential and helps to eliminate odors, so make sure your appliance is completely clean. Wipe down any crevices and clean the rubber seal to prevent mold and bacteria buildup. Then, run a cycle with hot water, baking soda, and vinegar to eliminate debris and odors.
2. Correctly Identify the Source of the Smell
Before taking any action, pinpoint whether the smell originates from the machine itself or the plumbing pipes. This will help you address the issue more effectively. To check if the smell is coming from the plumbing, disconnect the drain pipe and inspect it. If it's clogged or you smell a foul odor coming from it, clearing or replacing it may be necessary.
3. Pour Water Down the Drain Pipe
For an effective P-Trap, water is needed. To rule out a P-Trap problem, pour water down the drain pipe. This replenishes the water barrier, preventing sewer gases from entering your home. If the smell disappears soon after, the problem was likely a dried out P-Trap.
4. Reach Out to the Pros
If you still smell sewage after you’ve gone through all of these steps, there is likely a lingering plumbing problem or improper installation. It's best to contact a local sewer repair company to address clogged or improperly installed pipes since they can diagnose and resolve complex plumbing problems safely and efficiently.
Frequently Asked Questions
Yes, sewage smells can originate from a floor drain. If the P-Trap in the floor drain dries out or if there's a clog or other issue in the plumbing system, sewer gasses can escape through the drain, causing nasty odors. Regularly pouring water into the drain helps maintain the water seal and prevent those smells, but if the smell persists, you should have a plumbing professional inspect the drain for potential problems.
If the smell is closer to mildew or rotten eggs, the issue is probably mold or bacteria buildup in the machine or its drainage system. Clean your washing machine thoroughly, paying close attention to the rubber door gasket, as it can harbor odor-causing residue. Some machines have lint or debris filters that should also be checked and cleaned according to the user manual's instructions. Be sure to leave the machine's door or lid open after each use, as this allows for better air circulation and helps prevent mold growth.
Whether a DIY fix is safe depends on your knowledge and experience in plumbing and appliance repair. If you have the necessary skills, follow safety precautions, and consult the user manual, it can certainly be done safely. However, if you're unsure or lack experience, you should consult a professional plumber, appliance technician, or sewer repair company near you to avoid potential accidents, further damage, or plumbing issues.