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Why Does My House Smell Like Sewer When It Rains

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Who doesn’t love a good rain, right? In most places of the country, rain is welcomed and needed. The rain cleans the air around us and helps keep everything green.  However, rain can cause problems with your home. One of the first things homeowners worry about is their roof. Are all the shingles in place or is there a potential leak around the flashings.

What most homeowners hardly think about is how rain affects the plumbing in their homes. It can be common for a home to smell like a sewer when it rains. It isn’t pleasant, and you will want to get a plumber to come out and look at your problem right away. Below we will discuss several issues that rain can cause plumbing issues.

There are obvious issues like outside drains that get clogged. Anyone with outside drains knows that those specific drains get clogged up with dirt, grass, leaves, and other debris. You will notice when it rains, those outside drains become puddles and can turn into small ponds in your yard.

Outside drains usually aren’t the culprit of sewer smell but can be. Either way, when you notice those drains not working properly you need a plumber to come out and clear the debris. Flooding is one of the leading causes of damage to properties.

Sewer Gas

The first step is understanding what sewer gas is.  Sewer gas is gases coming from your sewage system that is produced by waste mixing with other household products going down your drains. The gas itself can be both non-toxic and toxic gases. This mixture can produce some very bad smells and include sulfur dioxide, ammonia, hydrogen sulfide, and other gases.

When your house smells like sewer during a rainstorm or just after a rainstorm, that is a sign you have some plumbing issues.  Below we look at some of the specific problems that can cause sewer gas.

Faulty Water Trap/ P-Trap

When someone refers to a P-trap or a water trap, they are one and the same. A P-trap is a critical piece of plumbing within your home as it stops sewer gas from seeping up into your home.  Each area of your home that has a drain of some sort should have a P-trap. This would include toilets, sinks, and laundry drains. When the P-trap malfunctions or breaks this is often the main reason for sewer smell within your home.

How to Fix

If you are handy enough, you may be able to fix the P-trap yourself.  There are some good videos online that will help point you in the right direction. However, for most of us, it might be best to call a professional plumber. In most areas of the country, plumbers give free estimates. A plumber can come out to your home and properly diagnose the issue and provide a free estimate for repairs.

Septic Systems

Septic tanks and septic systems can last a long time but not forever. Whether some homeowners neglect maintenance or tree roots cause problems septic tanks can fail. One of the more common problems is when there is a broken pipe. Rainwater will find the lowest point, and if you have a crack in your sewer line, your septic tank could begin to fill up. As the septic fills up with rainwater, it causes the sewer gas to rise and if you have a cracked or broken pipe, it will smell bad near your house. This can be unpleasant and embarrassing as the smell can easily travel to your neighbor’s yard as well.

Wax Ring

The wax ring at the base of your toilet helps keep a seal between your toilet and the drain pipe. When a seal is broken, it can lead to a toilet that leaks and a bad smell.  Sewer gas can leak up through your sewer pipes and when the wax ring is broken escape into your home cause an awful smell.

How to Fix:

When your wax ring is broken it will need to be replaced.  This requires the toilet to be drained and removed to access the ring.  Often times the previous worn out wax ring is in bad condition and needs to be scrapped off the toilet flange. You may want to use cleaner or vinegar to clean the area around the toilet flange prior to installing a new wax ring.

Floor Drains

This can be more common in commercial buildings but some houses have floor drains as well.  Usually, a floor drain can be found in a bathroom or kitchen.  A floor drain that was properly installed has a P-trap. If this P-trap is compromised then sewer gas can leak through and cause a nasty smell.

How to Fix:

Please reference our “How to Fix” section a few paragraphs above about P-traps.

Final Thoughts

Sewer gas can seep up through your existing sewer pipes anywhere you have a drain. When it rains, this can amplify the situation by pushing gases out. When you smell sewer in or around your home, that is a sign you have a plumbing problem, you should have fixed right away. In most cases, you will want a professional plumber to come out and assess the situation.