Many of us have been there. We wake up on a drizzly morning or walk into our home after driving on a rainy day and something just doesn’t smell quite right.

In fact, it smells pretty bad. Like the sewer is backing up or something! Yech! What is that smell and where is it coming from?

Obviously, something has gone awry. But why does it smell bad when it rains? Why does the house smell like sewage or poop?

Why Your Home May Have a Sewer Smell

A sewer smell in house can be extremely irritating, especially when you aren’t sure what the cause is.

  • It may be a crack in a pipe or other part of the sewer system.
  • It may be a loose sewer trap plug.
  • It can come up through the vents or plumbing system.
  • It may even be a problem with your septic tank (if you are on a septic system).

Either way – the issue should not be ignored and the cause of the problem must be found and corrected. It’s our experience that it will only get worse, not better.

So here are a few reasons as to why you may be smelling that terrible odor and of course, what to do about it.

Sewer Trap Plugs

There are many causes for a sewer smell but the most likely one is from missing or not well fitted sewer trap plugs. Either it’s come completely off or it’s become loose.

A sewer trap is U shaped – when water gets into the trap it naturally sits at the bottom of the trap. That water’s purpose is to act as a barrier between the sewer gases generated by the city sewer and your home or business.

If the sewer trap is not sealed as it should be with sewer plugs or they’ve come loose, then the sewer gas will escape and you will reap the benefits of it’s odor.

You or your plumber will find these plugs in the sewer access pit which are usually in the basement of your home.

To fix this issue, simply replace or tighten them and the problem of the foul smelling gas leaking out will be resolved.

Dried-Out Water Barrier

Another reason that you may be smelling your sewer is if the water barrier in the sewer trap has dried out due to lack of use.

This often happens when a fixture is not often used, such as a bathroom shower in the basement or a vacation home. A quick fix that may work, is running some water from that fixture. This fills the trap belly with water and helps to re-create the water barrier.

But if this doesn’t work – call the plumbers at Atlantis Plumbing because if you do smell sewer gas in your home or office, it must be taken care of immediately.

If You are on a Septic Tank

If your home or office building is on a septic tank and you are smelling a foul sewer odor when it rains, the cause may be any of the following reasons:

  • Cold temperatures may cause downdrafts from a plumbing vent stack. If you notice that the odor varies during the day (wind conditions would cause this) and if the odor tends to subside as temperatures warm up then this may be the cause of that sewer smell.
  • Often, when it rains, the atmospheric pressure changes, the air becomes heavy. As a result, the methane gases that are in the septic tank do not flow as they normally do through the vent. Instead, they remain low to the ground and this causes a foul smell, more like rotten eggs.
  • Of course, if your septic tank is full, the pump may fail and as a result, new wastewater will not come in to replace the old wastewater. Hence the smell.
  • The venting system in the septic tank may have become blocked. This often happens if you’ve had work done on the home or to your landscaping. If the vents aren’t working for any reason, the sewage gases can’t escape from the wastewater.

These problems can be addressed by using a sewer camera inspection service. It’s an efficient and cost-effective solution because it can identify the problem with great accuracy.

Septic tank problems should be dealt with early and by a professional sewer repair team.


If you suspect a problem with your sewer, call Atlantis Plumbing today at 770-505-8570.