Everyone loves the rain, I guess you are so. What if you wake up in the morning after heavy rainfall and you assume it will be a great day, spending time with your loved one with a cup of coffee, instead of this? It seems like the complete opposite.

Your house smells like sewer gas in the bathroom after heavy rainfall and immediately kills the mood. I know what it feels like to be in this terrible situation.

Instead of a cup of coffee, I’m guessing you’re wondering why my bathroom smells like a sewer when it rains.

Well, there is six probable cause for rotten eggs sewage smell in bathroom and houses too. The main cause is the Vent Pipe.

Let’s find out, and I’ll give some solution to fix the sewer gas smell in the bathroom, which instantly vanishes the sewage smell.

Why is a Sewer Gas Smell in The Bathroom After Heavy Rain? 

About more than 6 possible reasons for sewer gas smell in the bathroom after heavy rain, match according to the signs.

cause for sewage smell in house comes and goes

Number one Possible Cause for Your Bathroom Smell like Sewer After Heavy Rain Due to THE VENT STACK

The vent stack typically presents on the rooftop of the house. It controls the waste air, circulates the air pressure of the toilet drainage.

A plumbing vent is installed to prevent sewer gas backup. Toxic gases can easily escape from the house.

While after heavy rain and storm, there is possible that the stack may break or bend from somewhere, even the leaves or anything stuck within the plumbing vent stack.

A blockage vent pipe can cause a sewage-like smell all over the house. Clogging vent pipes always give you some warning signs.

Heavy rain can break the outlet pipe or crack the plumbing system of the house. If you notice sewage gas with some gurgling sound, then definitely create by the Plumbing stack.

Read More- How to Fix Vent Stack without getting on The Roof

Number two Possible Reason You Smell Sewer Gas in Your House When It Rains- DECOMPOSTING & BACTERIA FROM THE WASTAGE

When there are heavy rains, you have a nearby waste bin or sewage system that may increase the smell of all accumulated waste materials.

Most pits are composed of damp, human wastage, and gutter, which can cause a foul odor. The byproduct chemical gas is so toxic and creates the rotten eggs odor.

Number 3 Reasons Why does My Bathroom Stink when It Rains- THE SEPTIC TANK

Yes, if you have your own septic tank or have an old septic tank, then you can get a stinking smell usually when it rains outside.

The old septic tank is either going to overflow or the pipe will be torn out. An almost full septic tank backs up the waste and can’t hold within it.

Meanwhile, rainwater seeps into the waste products, causing odors throughout the house and bathrooms.

Again, rain causes air to be heavy due to humidity- thus the methane gas prevents it from running from the vent and leaking from the ground or toilet drain.

How do you get rid of the sewer gas smell from the septic tank in the bathroom?

Number 4 DRIED OUT WATER BARRIER is The Another Cause for your Bathroom Smell Like Rotten Eggs

Another possible reason for rotten eggs from the bathroom is the Dried out water barrier.

Water Barriers generally become dry because of lack of use. Many faucets or toilets in our houses use most often, so it is naturally arid.

To prevent the smell, run water through the pipe or used it frequently- the foul odor becomes less.

Again U-seal trap crack later sewer gas gradually release and spread all over the house.

Number5 POOR DRAINAGE CLOGGED Maybe The Cause for Sewage Smell in House Comes and Goes

Poor piping and drainage sometimes create several problems, particularly while raining. Heavy rain causes water to pile up the waste products and flood over the poor drainage.

A clogged drain shows the issue most. This way, depending on the climate, all waste becomes more easily decomposed. Guess what! You can face the already the foul odor.

When a drain becomes plugged, it is usually full of living stuff, such as leftover food, hairs, and household cleaners, rainwater force might cause the rotten eggs.

Read More- How To Unclog Drain ( Effective way) 

Number 6 Faulty P- Trap is The Another Reason For Make Your Bathroom Sewer Smell

P-trap is under your faucets. If you notice there is extra piping below your sink, you’re looking at P trap right now.

A P trap holds water by making a tiny bend in the pipe and forming a seal. The P trap balances the water level and prevents sewer gas from entering the system.  

As water drains through the P- trap, the air is pulled from an outside vent to equalize the pressure.

However, severe rain or snowfall may obstruct the vent, and the P trap seal may be sucked out with the draining water.

During this time, you may hear a gurgling sound as air is drawn into the sink drain, and you may begin to smell sewage coming from that sink.

Without access to outside air, the vacuum in the system might pull air from other plumbing fixtures.

For example, flushing the toilet could pull air from the sink, removing water from the trap. 

So if you smell sewage out of the sink drain after flushing, this could be a sign of a larger ventilation issue. 

Additionally, a buildup of waste can cause issues. Water might slowly seep out of the P trap due to capillary action caused by strands of cloth and hair along the pipe.

This is why it’s important to keep the P-trap clear of debris. 

These are all the possible causes for the sewer gas smell in the bathroom after heavy rain.

How do You Get Rid of Sewer Gas Smell in the Bathroom?

To prevent all this awful situation, follow these steps.

  1. We can’t handle natural calamity but can be safe from it. Use Vent Cap (Amazon) to prevent any object from stuck within it.
  2. For instance, to remove the sewage odor, use a toilet deodorizer. Around 15 minutes later, the homemade toilet deodorizer can absorb the smell, and you may proceed with the further process.
  3. Every ten years, alter pump out the septic tank.
  4. If you’re facing such a situation most often, then use the unused faucets and toilet.
  5. If any toilet is not used, just flush once a day. So it can wet the water barrier pipe.
  6. Clean the toilet and drains with normal Epsom salt. ( How to use Epsom Salt for drain Cleaner.)
  7. Call a licensed plumber.

Final Thought- Sewer Gas Smell in Bathroom After Heavy Rain

Nothing scarier than getting up in your own house, that stinks like sewage. I’m pretty much no one in your family going to love the rotten smell.

Sewer Gas Smell is not good for health. Even sometimes it is mixed with methane also life-threatening.

Besides health issues, the sewage smell is an indication of a bad vent system. It can overflow toilets in the future.

Don’t worry if you’ve tried and failed miserably to locate and resolve the sewer stench issues. As a result, only need an experienced plumber.


Q1. How to Find Sewer Smell in House?

A smoke test is a genuine way to detect sewer smells in the house. But, it will be better if you call an expert. 

Otherwise, you have to find it all by yourself. You need Uv nontoxic smoke and inject the vent stack.

Before that, cover the main sewer drain and other vents of your house.

After injecting UV non-toxic smoke through one vent pipe and watch which faucets or drains are infected. The smoke will come out from there.

Later you may detect the clog is happening where.

Q2. What does Sewer Gas Smell Like?

Sewer Gas AKA Hydrogen Sulfide, is a byproduct gas of human waste, bacteria, enzymes, etc.

At a low level of sewer gas seems like rotten eggs, which is the signature odor of Hydrogen Sulfide. It is harmful to health and causes eye irritation, breathlessness, fainting, etc.

Q3. The Unused Bathroom Smells Like Sewer?

If the unused bathroom smells like a sewer, it is most probably due to the P trap or the water barrier being dried out; because you are no longer using it.

The P-trap is to holds a certain amount of water in its bend and prevents the sewer gas from coming out. 

However, if the toilet is not used for an extended period of time, the water in the bend evaporates and gas escapes. 

In the ultimate case, you can smell a sewage smell from the bathroom.