How To Find Sewer Gas Smell In A House


Do you know how to find the sewer smell in your house? To begin, the first place you should look is your bathroom’s drains. 

In your shower, tub, or sink, the sewage smell could be from biofilm buildup, a byproduct of all the products we use to clean ourselves. Or, you might look behind your toilet or sink in an area called the P or S trap to find the sewer gas source. 

Don’t forget to check that your toilet is completely sealed to your floors since a loose toilet can let in sewer gas. The best-case scenario is a simple clogged drain. This is the kind of problem you can fix yourself with a plunger, drain snake, hot water, and some patience. 

However, if the cause of sewer gas is in your water heater or in your sewer line, experienced professionals are your best bet to solve the problem. 

An overlooked source of sewer gas smell is clogged vent pipes, and being that these are on your roof, may require someone with the right tools to eliminate the debris that is preventing sewer gas from being pushed out and away from your home. 

When you’re dealing with a major sewer leak or break, or the extent of the sewer gas is beyond “winging it” call HRS Restoration Services to get at the source of your sewer gas issues. 

HRS Restoration employs licensed, trained, and experienced team members. Our team includes contractors, electricians, and plumbers to tackle the many causes and fallout from sewer snafus. 

We’re standing by 24 hours a day, 7 days a week, and know how to check for sewer gas leaks. HRS is here to rid your home of noxious and harmful sewer gas. 

Call HRS Restoration at the first hint of sewer gas to make an appointment!

What Is Sewer Gas & What Does It Smell Like? 

Sewer gas is a nauseating stew of toxic and nontoxic gases. Sewer gas is the result of your household waste breaking down. Ok, but what is sewer gas really made of? 

The chemical components of sewer gas are hydrogen sulfide, ammonia, methane, carbon dioxide, sulfur dioxide, and nitrous oxide. It’s one of those “you know it when you smell it” type gases, and it smells terrible. Sewer gas can induce nausea and is sometimes likened to the smell of rotten eggs.

Is Sewer Gas Dangerous? 

Can sewer gas make you sick? The answer is yes. Given what it is made up of, it isn’t any surprise that sewer gas can be harmful to your health. This is especially true if you have a pre-existing respiratory illness or you are already immunocompromised. 

Usually, a brief exposure to sewer gas won’t have severe health effects but if you are exposed to sewer gas for an appreciable amount of time and you are already dealing with an illness, you may experience  fatigue, headaches, nausea, vomiting, dizziness, and an inability to concentrate. 

Causes Of Sewer Gas Smell In A House

In your search for how to find where sewer gas is leaking from, you might start with your bathroom’s drains. 

Consider everything that ends up in your drains, especially if you use a lot of products and have a lot of family members using your drains. Other causes of sewer gas odors in your home include  a dry P-trap, a loose toilet, or a clogged drain. 

Another cause of sewer gas could be blocked or clogged vent pipes. On rare occasions, it could be your hardworking but seldom thought about water heater. 

Sewer gas could be creeping inside by way of sewer leaks, sewer failure, or loose pipes. 

Below we discuss more about how to find a sewer gas leak in the house. 

How To Find A Sewer Gas Leak

Sewer gas leaks are often found in the bathroom but there are exceptions. 

Beyond the bathroom drains and pipes, you will also want to check your home’s kitchen, basement, and crawl space. 

Below we discuss each of these areas and what to look for in more detail. 


Telltale signs of sewer gas originating from your bathroom include sinks, tubs and toilets that drain slowly or are backed up. Other signs include pooled water near your toilet which happens when it is not properly secured to the floor. 

If your bathroom is not regularly used, the P or S traps behind the sink and toilet may have dried up, allowing sewer gas to enter your home. 


Your kitchen sink and garbage disposal put up with a lot of use and abuse. The grease, food, and other mystery debris end up coating the edges of your pipes and creating a blockage if you don’t pay it some attention. 

If your plumbing drain vent ( the long, narrow, vertical shaft connecting your main sewer line to the outside) becomes blocked, water could be siphoned from your sink trap, which creates a pathway for sewer gases to travel back into your home. 


An area where sewer gas might be brewing that doesn’t get as much attention is your basement. A strong sewer smell originating in your basement may be caused by a dried out floor drain, improperly vented appliances or fixtures, or even a damaged sewer line.

Crawl Space

When your main sewer line clogs, it can cause the water to back up in the pipe and spill into the crawl space. The soil in a dirt crawl space contains organic matter, such as leaves and manure that decay and emit odors. If the crawl space is unsealed, the terrible smell will travel upstairs. 

Unlike your vents coming from your bathroom and kitchen plumbing, your crawl space is not vented. Doing so would let in warm air in the summer and cold air in the winter. Whatever air is not vented will be inhaled as it rises from your crawl space. 

Preventing Sewer Gas Smells

There are a few ways that you may be able to protect your home from sewer gas smells. These include:

  • Ensuring that your basement is properly sealed
  • Check your water traps
  • Check the wax ring on your toilet
  • Check sewer for leaks
  • Doing simple drain maintenance each month
  • Run water through each sink and drain every month

When To Call A Professional

With our specialized equipment and experience, HRS will remove the sewer gas smell originating from a collapsed sewer line, clogged air vents, or an underground sewage snafus. Call us when you can’t find the sewer gas source or when the problem is beyond your DIY skills. 

We’re Denver sewage and cleanup removal experts available no matter what time sewer gas strikes. 

Why Choose HRS Restoration Services

HRS Restoration Services has a reputation for customer service and attention to detail. Our reviewers on Google rave about how we’re ready and able whenever disaster strikes and we’ll show the same care and attention to you and your home. Call us for more information about our sewer gas removal process. 

Our Process

HRS Restoration adheres to a three part sewage cleanup and removal process. First, we stop the breach when sewage tainted water is actively flowing or leaking into the premises. The next step is to get rid of water and waste from the affected area. 

Finally, we clean all surfaces and disinfect, sanitize, and dry everything the sewage water came into contact with. Below we discuss each of these steps in greater detail. 

Stopping The Breach

HRS will begin by stopping the source of the sewage leak or backup. This helps contain the spread of sewage and prevents any further exposure to you and your family. 

Our team of trained professionals may need to remove the water from toilets and what is trapped in the pipes connected to the drain system. We will also turn off the main water valve and patch leaks and cracks in your pipes.Removing Water & Waste In The Affected Area

Our restoration and mitigation teams remove any standing water with commercial grade vacuums and fans to stop the spread of mold and mildew and to remove the sewer gas smell from the air.  

Next, we remove sewage contaminated items and dispose of them if they can’t be salvaged. All discarded items are carefully removed in heavy duty trash bags to prevent further contamination.

Cleanup & Restoration

The cleaning process is extremely important given all the harmful health effects sewer gas can have. We will wash contaminated surfaces with a cleaning solution before disinfecting and sanitizing. We use EPA approved cleaning agents and bleach to disinfect. We also continue to dry the affected area as rapidly as possible using fans and dehumidifiers. 

Contact HRS Restoration Services Today!

Call HRS Restoration Services at the first signs of a sewer gas leak. Sewage inhalation and exposure is a risky business but we’re here to help!

Contact us as soon as you become aware of a sewer gas leak, and we will be ready to help!

Always Available

Anytime of day, any day of the year, HRS is here to fix what may seem overwhelming and intimidating. Our professionals in Denver are here to help 24/7.

what is iicrc and Why is it important?

IICRC stands for the Institute of Inspection Cleaning and Restoration Certification. Formed nearly 40 years ago, it is a non-profit organization that establishes globally recognized standards for the cleaning and restoration industry, as well as providing certifications, journeyman and master designation, and education.

By choosing a firm with IICRC certified team members, you are assured the cleaning professionals have undergone rigorous training and will handle your disaster restoration with the highest standard of care.


Helping Our Customers Immediately.

Figuring out what steps to take when disaster strikes can be a daunting task. HRS is here 24/7 to walk you through the process and bring your home or business back to habitable condition(s).

Taking care of emergencies so you don’t have to.

At HRS, we understand the panic that can set in when your basement floods or a fire breaks out at your business. We are here 24 hours a day, 7 days a week to repair damage and give you peace of mind.