Why Does My Basement Smell Like Sewage When It Rains?

Last updated:

If you’ve ever wondered why your basement smells like sewage after it rains, you’re not alone.

It’s common for basements to lack windows and doors, making it a place which stores sewage type smells, and removing the smells can be a real challenge.

To reduce the smell you first must find the source of the smell. Here we list a few possible causes and how to fix the issue.

P-Trap Issues

Your p-trap plays a critical role in preventing sewer gas from entering your home. If your p-trap is clogged, sewer gas will waft into your home, causing you to smell sewage.

The P-trap helps prevent this from happening by blocking the air from the drain with a trapped area of water. This way, the sewer drain pipe smells will not travel up the pipes into a room.

If you notice sewer gas odors coming from your drain, the P-trap could be clogged or have a problem with the vent pipe. These smells are very unpleasant, and they are a sign that your plumbing system needs repair.

In order to restore the water barrier around the P-trap, run a full load of water down the sink and toilet. This will re-wet the water barrier and help wash away any sewage smells. If you notice that your P-trap is leaking or has stopped working properly, call a plumber.

Check Valves Prevent Water From Flowing Back into the Drain

A check valve is a device used in stormwater systems to prevent backflow. Designed to stop water from flowing back into the drain during a storm, check valves are installed in drains and sewers to prevent flooding and overflow.

They are usually installed in close proximity to the water meter or right after the shut-off valve. Different types of check valves have different applications and can include reduced principle, pressure vacuum breakers, residential dual check valves, and more.

Using check valves in your basement plumbing fixtures can prevent a sewer backup during heavy rains or rapid snowmelt. In addition, check valves can also prevent sewage and gray water from creeping into basement drains. If a water backup occurs, an alarm can be installed to alert you to the situation. You can call a plumber to install a backflow preventer valve.

Loose Toilet Can Cause a Rotten Egg Smell of Sewer Gas

A rotten egg smell might be coming from sewer gas from a loose toilet.

If you’re experiencing a rotten egg smell after it rains, the cause of the problem may be your septic tank’s drainage system. A burst sewer pipe, clogged drain pipes could all be the cause of your rotten egg smell after rain.

An improperly installed toilet washer or a clogged vent can also cause sewer gas to emanate indoors. Rain makes the air in your home heavier and sewer gases cannot escape.

If you have a loose toilet, the first step to fixing the problem is to check the seal of your toilet. If there is any leakage from the toilet bowl base, you can repair this by applying fresh caulk around the area.

A broken wax ring under the toilet – the seal between the toilet and the pipe could be the problem. This can be fixed by replacing the wax ring.

Fixing a Clogged Ejector Pump

If you’ve noticed that your basement is beginning to stink when it rains, you may need to fix your ejector pump. This pump is used to drain wastewater from your home and should be vented or covered. If your pump is clogged, sewer gas and other smelly materials may be getting into the basement.

To fix the problem, you should first check the ejector pit lid and ensure that it’s in place and has a tight seal. Next, check the piping that discharges water to the outdoors.

The p-trap in your ejector pump can also be dry and may be letting out foul odors. You should check the p-trap every once in a while to make sure it isn’t allowing sewer gas to escape. If it’s not, then you can use baking soda and vinegar to clear the smell.

If you can’t eliminate the bad smell from your basement, try cleaning the drainage system. In general, a sump pump can’t remove all the sewage that has accumulated. So, you need to clean the entire system thoroughly to remove any odor-causing bacteria. Once you’ve done this, you can try the following fixes:

If you notice a sewage smell coming from your basement after a rainstorm, you may need to fix your sewer line. You can also check for leaks in the toilet wax ring. If these methods don’t work, contact a plumber to determine the root cause of the problem.