You walk into the basement and all of a sudden, you get a faint whiff of rotting eggs. The farther you travel down the stairs, the stronger the stench gets. Unless you’ve left a plastic container of deviled eggs sitting on a table for a week, the pungent odour is coming from your plumbing. It’s a clear sign that there is something wrong with your home’s system and you need to call a professional.

What is that smell?

The simple answer to that question is sewer gas created from the decomposition of waste. The more specific answer is that sewer gas contains a mixture of toxic and non-toxic components, many of which are odourless. The gas “hydrogen sulphide” is the exception. It lets off a strong smell that is similar to rotten eggs.

Why should you be concerned?

A functioning plumbing system and an effective vent system makes sure that sewer gas is unnoticeable to the residents — they will only detect the smell of hydrogen sulphide when something is wrong. Here is a list of possible reasons that made the stench enter your house:

• A broken or faulty clean-out cover
• A faulty or missing vent pipe
• No primer or defective primer
• A broken pipe connection
• A loose pipe connection
• Poorly installed traps
• Sewer back-up

You will most likely smell this odour when you are walking around your home’s basement. Hydrogen sulphide is heavy, so it’s not going to travel up to the second floor or the attic. It will sit at the lowest level and smell strongest closer to the floor. Basement floor drains are popular culprits for letting out sewer gas because of dried-out water seals.

Inhaling sewer gas is not good for your health. Low levels of hydrogen sulphide will cause numerous symptoms, like:

• A sore throat
• Coughing
• Eye irritation
• Headaches
• Fatigue
• Dizziness

You should also be concerned about smelling hydrogen sulphide in the house because it indicates that methane gas is there, too. Methane is odourless on its own and can be very dangerous. In high concentrations, this chemical gas can be explosive. As a precaution, don’t ignite anything or create open flames when you smell rotten eggs — call for sewer odour inspection services and wait for the problem to be resolved. In the meantime, open up the windows and let fresh air circulate inside the house.

How do you fix it?

When you smell this particular odour, you should call a trusted plumbing company in Toronto to investigate your house to find out where the sewer gas is coming from and what kind of repair you need. It could be a quick fix, like replacing a water seal on a floor drain, or it could be an intensive project like replacing a broken pipe connection. When you get a professional diagnosis, they will let you know exactly how to remedy the problem.

If the odour is coming from sewage backing up into your home plumbing system, there are measures you can take to prevent the problem from happening again. As a homeowner, you should take good care of your pipes from now on. Don’t flush items other than water, human waste or toilet paper down the toilet. Don’t pour cooking grease or oil down your kitchen sink because they will harden and coat the pipes. Insert drain catchers into your sink, shower and bathtub drain.

Another measure that will keep sewer gas out of your house is getting a backwater valve installed. A backwater valve will turn your sewer line into a one-way passage so that only household waste can exit it. If you don’t have a valve installed, the sewer line can act as a two-way passage between your home and the city’s sewage system.

When the city’s system gets overwhelmed with water, it sends the overflow up through your main line. The disgusting mess typically happens during heavy rainstorms and floods. Getting the valve inserted into your basement will prevent sewer back-ups from happening — even if the city’s sewage creeps up toward your house, the cap will stop it from reaching your drains.

If you’re considering taking this preventative measure, you can call us for a free estimate to see how much the installation will cost in addition to the sewer odour repairs. We can help you obtain a subsidy of up to $1,250 for a backwater valve from the city of Toronto to make the investment easier on your wallet. 

What if it’s not sewage?

Famous home expert Mike Holmes claims that a strong home odour similar to sewer gas could be coming from your walls and not from your plumbing. Your home could have toxic drywall, which contains sulphur. When the surrounding area is hot and humid, toxic drywall lets off sulphurous gasses that smell like rotting eggs.

North American builders used toxic drywall manufactured by China to keep up with residential construction demands between 2001 and 2009, without knowing the materials were harmful. If your property was constructed during this period, it’s possible that your walls contain toxic drywall. Other than the stench of rotten eggs, you can tell there is something wrong with the following clues:

• Corrosion of copper pipes and wires
• Tarnishing of silver
• Failing electronics
• Health problems like eye irritation, headaches and nosebleeds

If you’ve had your house inspected by plumbers and they can’t seem to find any issues with your system, you should call a professional to check the walls. Toxic drywall should never be ignored, even if you only have a couple of sheets of it in the house. Have the whole property expertly examined and have any of the contaminated sheets removed and replaced as soon as possible.

If you smell rotten eggs in your basement, your first instinct should be to call your plumber, not to pull out the air freshener or light scented candles. A foul and persistent odour is a warning sign showing you that there is something wrong. You should always listen to what your home is trying to tell you.