Toilet Smells Like Rotten Eggs? No, It's Not Something You Ate

Inside of a toilet tank
Sewage smells like the worst kind of rotten eggs. If you ever notice that telltale sulfur odor coming from your toilet – don’t ignore it. It could be a sign of something serious. Keep reading for what you need to know.

What is That Horrible Rotten Egg Smell?

Sewer gas is primarily methane, which is odorless, but one of the other gases in the mix is hydrogen sulfide, which smells like rotten eggs. The hydrogen sulfide results from the breakdown and decomposition of organic matter (the raw sewage). Ammonia and carbon dioxide are also in the mix. All of these gases are toxic to humans.

Why Doesn’t My Toilet Always Smell Like Rotten Eggs?

You couldn’t stand to live in your house if you could always smell raw sewage. That’s one of the great things about modern plumbing. It allows sewage and sewer gas to move out of your home completely unnoticed. If your plumbing system is working properly, you should never smell rotten eggs from your toilet or pipes.

Why Does My Toilet Suddenly Smell Like Rotten Eggs?

There are three common reasons why you could smell sewage in or around your toilet or bathroom:

  1. The first is a dry trap. This happens when a toilet isn’t used for a long time. The water in the pipe dries up, allowing the sewer gas to back up into the toilet. The gas rises through the water in your bowl and out into the room. If you notice rust stains in a toilet, it could be a sign of disuse, and hence, a dry trap.
  2. Another common cause is a clogged toilet or drains that can cause the smell to start in your bathroom.
  3. A more serious issue could be a broken drain line or vent pipe. This will affect more than just the bathroom. It could make your whole house smell terrible.

Is it Dangerous That My Toilet Smells Like Sulfur?

If you get a passing whiff of sewer gas or the smell is very faint, it’s not going to be hazardous. When it does become an issue is if the smell is strong or if it’s left untreated. The methane in sewer gas can displace oxygen, which can create a deadly situation, especially in small spaces. Plus, the gas carries bacteria. For multiple reasons, yes, sewer gas is dangerous.

What Should I Do if the Toilet Smells Like Rotten Eggs?

If you have a clogged toilet accompanied by a rotten egg smell, don’t try to manage it yourself. The bacteria from the contaminated water in combination with the potentially dangerous sewer gas is nothing to mess around with. A professional plumber can clear the clog, find the source of the smell, and correct it quickly and safely.

For help, you can count on the team of trusted plumbing professionals at Mr. Rooter® Plumbing. Our customer-friendly technicians are available 24/7 for sewer gas emergencies and can fix the problem even if you need a new toilet or a new sewage vent pipe. Contact your local Mr. Rooter today.

Need help getting rid of other bathroom smells? Check out these ventilation tips from Aire Serv. Just like Mr. Rooter, Aire Serv is part of Neighbourly’s community of trusted home service providers. If you’re looking for qualified home service providers in your area, visit