Basement Smells Like Sewer? (5 Reasons Why)

By |Published On: November 4th, 2020|Categories: Residential Plumbing, Sewer Systems|

What Is That Awful Smell?

If you can smell rotten eggs, that’s a sign that there is solid and liquid waste creating an unhealthy chemical combination. It’s hydrogen sulfide and it is not safe! If you do not find the source of the problem in time, you can become incredibly sick showing signs of:
  • headaches
  • vomiting
  • trouble breathing
  • loss of memory
  • lack of concentration
  • loss of smell (the smell will appear to go away)
  • eye irritation
  • lung irritation
  • seizures
  • coma

Basement Smells Like Sewer

If your basement smells like sewer, it could be due to multiple causes.

These signs are scary and can become a reality if exposed to these gases for a prolonged time.

Most of the solutions to these problems can be done yourself. If they do need professional help, you can call us at New Flow Plumbing.

Where Can That Awful Smell be Coming From? How To Fix It

The most common cause of sewer odor leaking in your basement will be from a large floor drain.
This drain runs deep into your sewer line and can give off that horrid smell due to multiple causes.
Note: If you have any concerns with finding the source of the issue, feel free to call us at New Flow Plumbing for our personal help.
  1. Dried-out water trap
Underneath your kitchen and bathroom sink, there is a U or S-shaped pipe that keeps a small amount of water. It’s there to prevent sewer gas from entering your home.

They also exist under basement floor drains and laundry tubs. If left unused they can dry up and eventually evaporate. That’s when you smell that odor.

Basement Smells Like Sewer

A U or S-shaped pipe keeps a small amount of water to prevent sewer gas from entering the home.

Take a gallon of water and pour it down the stinky drain. This should refill the trap and stop the odor.
  1. Missing cleanout plug
Your basement floor also has a floor drain with a trap underneath that. But this trap contains a section that bypasses the water trap. There is a little plug that stops the sewer gas from coming up. Every time you clean the drain, this plug needs to be put back in place. If missing, that’s when you smell that nasty odor.
Simply enough, any hardware or plumbing store will have one you can purchase.
  1. Toilet trap
If you have an unused toilet that gets rarely flushed, the trap can also evaporate and allow gas to enter.
Flush the toilet. SOLVED!
  1. Toilet wax ring seal

Where the toilet meets the floor is a connection called a toilet flange, and that connects to the drainpipe. Between the toilet and the flange, there’s a wax ring seal. If this seal is not tight and your toilet is wobbling, sewer gas can enter your home. If you have a bathroom in the basement, this can be the source of that awful stench. The seal can even dry out and cause the issue.

Basement Smells Like Sewer

The toilet wax ring needs to be sealed otherwise smell can enter your house or basement.

Just like the drain plug, if it’s defective, simply remove the toilet and replace the wax ring.
  1. Ejector pit(call us)

What is an ejector pit? Inside your basement, you may have a bathroom or laundry room with an ejector pump. Sewer systems use gravity and the basement needs a pump to reach the sewer line. So the ejector pump helps waste go where it needs to go. The ejector pit (also called a sump basin) is where the pump is located and needs to be properly sealed and vented. If anything looks broken or cracked, that’s where the sewer gas is entering from.

Basement Smells Like Sewer

Ejector pit (also called a sump pump) is where the ejector pump is located. This could be where the sewer odor is coming from.


If the seal is secure and the pit is vented, the issue may be an actual component. Something is either damaged or missing. This particular issue may require professional help, which again we are here to offer.

Read more about: How To Get Rid Of Smelly Drains

If That Doesn’t Work: Trenchless Sewer Repair

Do not let the problem continue unresolved. It is unhealthy to breathe in sewer gas and exhaust odors. Besides the basement, the smell can travel into your kitchen and other bathrooms. No one wants to live with that toxic smell for longer than they have to.
It’s even possible for your brain to start ignoring the smell as if it went away. It hasn’t! Your nose can lose its sense of smell and disguise the culprit.
If the problem is larger than the issues mentioned above, it could a broken drain line. But no need to panic! With trenchless sewer repair, we can fix a broken drain line in just a few hours without the hassle of conventional sewer repair. Trenchless sewer repair is cost-effective, time-saving, and is a lasting solution with 50 – 100 years of efficient results.
Using trenchless sewer technology, we save property owners between 30 to 40% of their entire project cost. It’s a more cost-effective solution than the usual methods because we won’t destroy your property. You will save thousands of dollars on restoration and clean up costs from normal replacements and avoid all that unneeded hassle.

Whatever the issue is, if you need help, we are gladly willing to offer our services here.

Basement Smells Like Sewer

Let’s eliminate that basement sewer smell.

About the Author: Arman

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