Sewer or Rotten Egg Smell at Night? Top Causes

If you notice a sewer-like or rotten egg smell in your home, you may be dealing with a serious issue. Though you should always take a sulfur smell seriously, it doesn’t always mean danger. 

A rotten egg or sewer smell can come from a gas leak in your home. It may also come from dry pipes in guest bathrooms that you don’t use all the time. Less commonly, this can also happen with a water heater issue, old drywall, or actual rotten food in your home. 

This article will discuss these possible causes and how to keep yourself safe when you notice a strange smell. 

Why Does My House Smell Like a Sewer Only at Night?

There are many different causes for a rotten egg smell in your home. If you are experiencing strange smells, they may be more pungent at night. 

Reasons You May Only Smell It at Night

  • If it is cold at night, the air may not run during the day
  • Less movement allows the smell to linger
  • You are out of the house for most of the day
  • Running more appliances at night 

Only smelling the rotten smell at night can mean many different things. We use a lot of different appliances at night and tend to require more heating as the sun goes down during the Winter.

Sleeping in a warm environment is vital for our sleep patterns (source: Yahoo). So, you can’t really avoid it. Noticing these smells at night is normal. 

A gas leak is one of the most dangerous potential causes of a late-night sulfur smell. This should always be your first concern when you smell something rotten. We recommend contacting the fire department or the utility company to come to test your home for a potential leak. 

safety specialist checks a gas stove

This will be much more noticeable at night as your heat runs more and there is less airflow to cover the smell. A gas leak should be the very first consideration for this smell, as it is the most dangerous. 

Why Would My Bathroom Smell at Night?

If you notice a rotten egg smell in your bathroom at night, you may be dealing with dry drain pipes. This can happen if you do not use the bathroom often, and the pipes can dry. An infrequently used bathroom can draw sewer gas through the pipe and into your bathroom.

It can make your bathroom smell awful, but you can fix it by ensuring that you flush regularly. 

If you notice this in your bathroom, it may happen more at night while you sleep if you do not use that bathroom often. What you are actually smelling from the sewer pipe is methane, which can give off a very rotten, sulfur smell (source: ScienceDirect). 

AC Vents That Smell Like a Sewer at Night

If you have already ruled out a gas leak, some other potential issues can create a sewage smell in your vents at night. The smell may come from a backed-up sewer line or a rupture sewer pipe. Both of these problems can cause your vents to smell bad and fill your home with methane. 

Unfortunately, high levels of methane exposure can cause several health problems.

At higher levels, exposure to methane can cause headaches, mood changes, nausea, vomiting, vision loss, and memory loss (source: Public Health England). So, it is best to contact a plumber immediately to handle this. 

If the smell does not come from blocked sewage, other possible causes exist. One of the main concerns with a sour smell in air vents is condensation. If your AC unit is not draining properly, the condensation left in the vents can be a breeding ground for bacteria and mold

Air conditioner vents

If you have ever forgotten to put your clothes in the dryer, you probably know that sour, moldy smell. This can happen in your air vents if water can sit in them.

Mold can grow just about anywhere we allow it to, and it can cause reactions in people exposed to it over a long period (source: The Center for Disease Control and Prevention

What Would Cause a Sewer Smell Outside at Night?

The most obvious cause of a sewer smell at night outside of your home is an issue with the sewer line. If there is any damage to pipes or blockages causing the line to clog, it can cause a sour smell outside of your home. 

This can happen even more at night due to the wind blowing the smell toward your home. Heat can also cause the smell to get even worse. So, if it is especially hot during the day, you may begin to notice a smell that you didn’t before. 

If the sulfur smell comes from inside your home, there is very little chance you will smell it outside. So, treat unfamiliar outside smells differently than inside smells.

You should still contact a plumber to get the best possible advice on handling drainage problems, but smelling it outside indicates it is not a problem with a gas leak. 

In conclusion, you may smell many different things. If the smell gets worse, we recommend contacting the fire department, which can quickly test for a potential gas leak.