Since the bathroom is one of the most important rooms in a house, it is never a good time to smell rotten eggs coming from the toilet. If you do smell something that resembles rotten eggs coming from your toilet, then you need to resolve it as quickly as possible. 

Most likely, if your toilet is smelling like rotten eggs, then it is the cause of sewer gas. If the smell is coming from the septic system, then it is because of bacteria, while if the water is the source of your smell, it may only be one pipeline that is impacted.

Whatever the reason that sewer gas is coming into your home, you need to be able to properly identify it, and call a plumber, before it becomes a bigger issue.

What is Sewer Gas?

This case is created when the waste from your toilet breaks down and your sewage and sludge goes through a decomposition process. Sewer gas is a mixture of a few other types of gases. Although most of these are non-toxic, there are others that are.

Typically sewer gas is mostly made up of methane gas, carbon dioxide, hydrogen, ammonia, nitrogen, and sulfur dioxide.

Since methane has the ability to displace the oxygen, it can actually be potentially deadly. Methane combined with hydrogen as well as sulfur gas makes sewer gases very hazardous to your health.

Where is the Smell Actually Coming From?

The rotten egg smell coming from your toilet means that something in your plumbing lines is not working properly. This means the smell could be coming from a few different problems.

Dry Trap Problems

Your dry trap is a part of the sewer system that where all the drains come together. It is called this because it is shaped like the letter “P”. This trap typically contains water, but also a seal that helps to keep sewer gas odors out. When water evaporates from this, it may allow sewer gas to enter.

Breakage or Leakage

If there is a break or a leak in your drain line, then you definitely have a problem with your sewer system. This may be a reason for the rotten egg smell coming from your toilet. Because of this, the smell of sewer gases may even go into other parts of your home as well.


Another common reason for the development of the rotten egg smell from your toilet may be a bit more serious, a blockage.  This clog might be at or near the drains, or it can be within the toilet, but it could also be within the septic tank. The reason this occurs is that the sewage is not being allowed to flow into the septic tank. Because of that, the sewer gas backs up into the drains or into the toilet.

Cracked Pipes

Sewer system pipes are reinforced. This is done in order to protect the inside of your home from your own waste. When your pipes crack or break, you run the risk of having a rotten egg smell.

Blocked Air Vents

Air vents diffuse toxic gasses away from your home. When your air vents are blocked, they will not be able to vent your home properly. This can occur due to dirt or debris, but always need to be cleaned to prevent sewer gas building up, then leaking into your home.

Loose Toilets

If you have a loose toilet, you may be allowing sewer gas to leak into your home. This is because loose toilets can cause gaps in the pipes. To protect yourself from this happening, your toilet needs to be tightly fitted to the sewer lines. 

Other Reasons Your Toilet May Smell Like Rotten Eggs

There are three other reasons your toilet is smelling like rotten eggs. The first is simply due to a clogged toilet. Although this may also smell like human waste in general, it can also mimic rotten eggs.

If you have a more serious issue, such as a broken drain line, or vent pipe, then you will have more trouble than your toilet. This might affect your entire house and make it smell horrible. If this occurs, contact your plumber immediately and get out of your home.

The final reason your toile may smell like rotten eggs is due to a dry trap. This happens when you have not used your toilet for a long time. Dry traps occur when all of the water in the pipe dries up, and sewer gas backs into the toilet. One sign of a dry trap is rust stains in your toilet.

Can Sewer Gas Make You Sick?

Sewer gas does have the potential to make you sick. If there are low levels of sewer gas in your home, then you most likely will not be sick from it, but if there is a lot of sewer gas in a small area, there are huge health risks.

Do not fear, there is not a huge danger with sewer gas being released in your home. The main danger occurs if you were to make an attempt to enter the septic tank, or a large hole appears. Make sure to avoid a hole, tunnel, or some other large opening in your septic tank, and call a plumber if this occurs.

Exposure to Sewer Gas Symptoms

Although the first sign of sewer gas in your home is rotten eggs, you may also experience symptoms of sewer gas exposure. This might include:

  • Fatigue
  • Vomiting
  • Headaches
  • Nausea
  • Dizziness
  • Feeling lightheaded
  • Poor memory
  • Bad concentration

High levels of sewer gas exposure typically do not occur in the home, but if they do, symptoms of high levels of sewer gas may include:

  • Loss of smell (this means you will not even be able to smell the rotten egg odor anymore)
  • Mouth, throat, and lung irritation
  • Eye irritation (may include pink eye)
  • Seizures
  • Coma
  • May result in death

What To Do If You Definitely Have a Sewer Gas Problem

If you have a clogged toilet and there is a rotten egg smell, then you definitely have a sewer gas leak or problem. Do not try to fix this yourself. The reason for this is because the bacteria in the contaminated water s a combination of toxic gasses. Instead, hire a professional plumber. They will be able to clear the clog, find the source of the smell, and safety fix your problem.

Related Questions

If sewer gas is the reason for my toilet smelling like rotten eggs, why don’t I always smell it?

If your toilet always smelled like raw sewage it would not be a very good way to live. This is why modern plumbing exists, it allows this sewer gas to move out of your home. If your pipes are working properly, they will move the sewer gas out of your home, and you will never smell it.

If my toilet smells like rotten eggs, is it dangerous?

If you only smell a slight smell of rotten eggs from your toilet then you do not have much to worry about. You should only be concerned when the smell sticks around for a long time untreated. This gas carries bacteria and you do not want it to hang around for too long.