Why Does My House Smell Like Sewer Gas?


Have you ever passed your sink or toilet and noticed a less than pleasant odor coming from it?  You most likely smell something referred to as “sewer gas.” This is an odor that is typically a mix of hydrogen sulfide, ammonia, carbon dioxide, methane, nitrogen, and hydrogen.  

The odor typically poses no risk to the members of the household, except in extreme cases.  Hydrogen sulfide is a toxic gas, however, it is such a low concentration in the sewer gas that it does not pose a threat to the household.  The smell, however, may irritate those in the house.  In high enough concentrations, it may cause sore throat, fatigue, or shortness of breath.  These symptoms typically only occur after long term exposure.

How does this smell enter your house?  Is there a way to get rid of the smell?  White’s Plumbing has the answers for you.

What Causes Sewer Gas Smell?

Sewer gas odor gets into your home when something is wrong with your plumbing. These instances include small faults in the plumbing, as well as more serious ones.  The most common ones that cause sewer gas smell are as follows:

Dry or Damaged Water Traps

When your water traps in your home – sometimes known as p-traps or s-traps – dry out, this allows sewer gas to easily move into your home.  These water traps are under every sink in your home, as well as near floor drains and bathtubs.  If the trap has a crack or hole in it, sewer gas easily moves into the home.  Often, when the trap is broken, it easily dries out.

There are two fixes to this issue.  The first is to either run your sink for a few minutes or pour a pitcher of water into the drain to wet the trap again.  Once the trap is wet, it should function properly again and stop smelling like sewer gas.

The second fix is to fix the damaged trap.  The trap should not have any cracks or holes in it, therefore preventing it from drying out.  Home Depot provides a guide on how to replace your sink trap.

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Bad Toilet Wax Ring

Your toilet should have had a wax ring installed at the base when placed in your home.  This ring is waterproof and airtight, preventing any water seepage and keeping out the smell of sewer gas.  When the wax ring goes bad – or was never properly installed – this not only allows water to get through and grow bacteria, but also allows sewer gas inside your home.

In order to fix this, you need to replace the wax ring.  This definitely requires more effort than fixing a damaged water trap, so hiring a professional like White’s Plumbing may be a safer choice.  However, there are step-by-step instructions for fixing your toilet wax ring.

Sewer/Septic Pipe Leak

Issues with your sewer and septic pipes are harder to discover since they do not originate from inside your home.  This often requires a plumber to fully diagnose and solve the issue. However, there are warning signs that you may have a broken pipe or leak.  If you notice these issues in your home, you may want to consider calling a plumber:

  • Sewer gas odor, but no other issues that would cause the odor
  • Constant running water or trickling water in the walls
  • Cracks in your home’s foundation
  • Sunken wet patches in your yard or especially lush grass in specific areas
  • Water bill suddenly raises
  • Slow water drainage
  • Water pressure suddenly drops
  • Water changes color

How to Prevent Sewer Gas Odor

Just because a home may not smell like sewer gas does not mean that it cannot happen eventually, or something may not be wrong in the plumbing that will eventually cause sewer gas to enter the home.  There are measures you can take to keep your home in its best condition:

Regularly Keep Water in Traps

Since one of the most common causes of sewer gas odor is dry drain traps, it helps to regularly make sure they all have gotten water recently.  Similar to fixing a dry trap, run the water in the sink for a few minutes or pour water down the drain every once in a while to keep them moist.

Additionally, to keep them from drying out so fast, you may pour a tablespoon or two of vegetable oil on top of the water to keep the water from evaporating as quickly.  This way, drying of the drain will not become a problem as often.

Keep Drains Clean

Let’s face it, one of the most common reasons a plumber is needed is for a clogged drain.  Regularly cleaning out your drains of all the debris that gets in there, such as hair, food, small toys, etc. will prevent them from clogging so easily.  This also prevents them from breaking and cracking the pipes as well.

Oftentimes, bending a wire hanger and inserting it a few inches into the drain will help pull out any items that got caught in there.

Contact White’s Plumbing Today

If you are in the Youngsville, North Carolina area and are concerned about a sewer gas odor in your home or any other plumbing issue, White’s Plumbing is here to help.  We help with plumbing problems of all shapes and sizes – even emergencies.  Feel free to give us a call today so we can get started on finding the cause of your sewer gas odor in your home.

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