House Smells Like Sewer When It Rains

So Your House Smells Like Sewer When It Rains? Here Are 4 Remedies

I love those rainy days. The soft pitter-patter of the raindrops on the trees creates the perfect ambiance to relax with a cup of tea and a good novel.

But, what if the house smells like sewage after it rains?

One side effect of rain is it can mess up your plumbing system. So if there’s a smell, you need to fix the issues with the system without delay.

Let’s find out how to go about it.

What Makes the House Smell Like Sewer When It Rains?

When there is a foul odor in the house, you can blame it on the sewer system or the washing machine (which can ALSO smell like sewage!) in most cases. And the main reason behind it is bacteria.

The human and organic waste generated in a home is carried out through a network of pipelines. When too much waste is dumped into a sink, the pipes or the drains can get clogged. The bacterial decomposition of this organic matter causes a horrid smell. 

Some of the common gases that cause this foul smell are ammonia, hydrogen sulfide, sulfur dioxide, and methane.

However, there can be other causes behind the foul smell on a rainy day as well. Take a look.

1. Blame It on the Septic Tank

If your sewage system is dependent on a septic tank, it can be the main cause of the odor. The rainwater might run into the septic tank and cause it to overflow. If the tank is already full or the drain field is saturated, the foul gases might escape into the surrounding area.

When the rains continue for long periods, the air becomes heavy. So the gases in the tank may not flow as they usually do. They might settle at the bottom and generate a foul smell. 

Septic Tank 1

If the septic tank is old and of insufficient capacity, the chances of sewer leakage are high. Think of replacing or moving the tank to a new location.

Also, the venting system of the tank can get clogged. This will prevent the gases from escaping. You can simply remove the debris that’s blocking the vent opening.

The drains leading into the tank can get blocked too. If the sink or toilet is bubbling or gurgling when flushed, it can be due to a clogged drain or a blocked vent stack of the plumbing system.

2. Cracked Sewer Lines

The surface runoff can enter the sewer lines through a crack and push out the gases. At times, the waste materials can escape from a broken or damaged sewer line and generate a foul smell. 

If you have a sewer line running through the yard, it might get damaged by roots. The chances of damage are higher if you have plastic sewer lines.

You need to take the help of a professional team for tackling such issues. The lines need to be inspected by an expert with specialized equipment to locate the exact spot of leakage.

3. A Dried P-Trap

The P-traps are U-shaped bends in the sewer lines. They are also called water barriers.

Since the P-trap holds water, it prevents the sewer gases from coming out through the drains. The gases are forced out through the vent in the pipeline.

After all, that’s why toilet bowls always have those little puddles of water at the bottom!

Your kitchen sink (as well as any drain in your house) has them too, even though you can’t see all of them.

Let’s say you were out on a vacation and the sewage system was not used for a long period. That can cause the water in the P-trap to dry out. Without any water to act as a barrier, the gases from the lines can come out and invade your house.

Pro-tip: Pour some mineral oil or cooking oil into the sewage system before you head out for a long vacation. The oil will slow down the evaporation rate of the water in the P-trap.

Dried P-traps can be fixed by pouring water into them. However, if the P-trap is broken or damaged, you need to replace it. For that, take help from a professional.

P Trap

4. Damaged Ring of Wax

Does your toilet seat feel wobbly? Then the wax seal at the base is broken.

The wax ring at the base of the toilet forms a seal that prevents the gases from the drainpipe from leaking out. A broken seal can also cause a sewage spill on the floor

If the wax ring is damaged or broken you need to replace it. The good news is, that wax rings are cheap and won’t cost you much.

Replacing the wax ring is not a difficult task. You need to lift the toilet, install a new ring, and then place it back. However, if you are not a confident DIYer, it’s best to take professional help.

Why Does the Sewer Smell Increase When It Rains?

When it rains, the high moisture content in the air makes it heavy. So the released gases are unable to get away from the house. That makes the sewer smell stronger.

During the night, the temperatures drop and the density of the air increases further. So, the sewer gases remain low at the ground level and saturate the air around the area. 

That’s why you might find the smell getting worse over night.

As the temperatures rise during the day, the air becomes lighter and the gases can flow away from the vent. So the smell comes down.

Often, the smell is concentrated around the basement. This is because the pipelines in the basement are at the lowest level. So, problems like clogging are likely to occur here first.

Some homeowners also complain of sewer smell in the house when the wind blows. If the vent has been installed wrongly or near a window, the sewer gases can enter your home on a windy day.

How to Prevent Sewer Smell in Your House When It Rains?

Girl Pinches Her Nose

The first step to get the smell of sewer out is to open all the windows. Then you can sprinkle some baking soda over the floor or carpet to neutralize the odor. Allow it to sit overnight and vacuum in the morning. Spraying vinegar can also help.

Other than that, you can also use a chemical odor eliminator to get rid of the smell.

For a damaged septic tank, broken pipes, or blocked drains, you need to take the help of an experienced plumber to locate the source and solve the problem.

In case of clogged lines below the sink or the shower, you can try a simple home remedy to clean up the gunk.

Here’s what you need to do.

  • Mix ¼ cup of baking soda into a cup of vinegar.
  • Pour it into the clogged drain. Let the mixture sit for 2 to 3 hours to allow the chemical reactions to take place.
  • Then pour a gallon of cold water into the drain to wash it off
  • In addition, you can also pour some chlorine bleach into the drain to remove the blockage. Let it settle for an hour and then wash it with cold water. However, if you are using a septic tank, the chlorine can harm the bacteria in the tank. In that case, stick to natural remedies.

Frequently Asked Questions

Why does my house smell like sewer in the winter?

If your house smells during the winter it might be due to a frozen septic tank or pipelines. Besides, cold temperatures can also cause downdrafts from the sewer vents. This may spread across the house and cause the smell.

Why does the septic tank smell when it rains?

The excess humidity in the air during rains may not allow the gases from the septic tank to escape properly. Besides, rainwater might be draining into the septic tank or the drain field can get saturated with water.

Will the sewage smell go away?

The sewage smell will not go away unless you locate the source of the problem and fix it. It’s best to take the help of a professional plumber to do it in the right way.