Why Does My House Smell Like Sewer

Help! Why Does My House Smell Like Sewer?

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Last updated on December 7th, 2021 at 07:59 am

Imagine waking up to a pungent odor that reminds you of a backed-up sewer. An unpleasant smell, especially a sewage smell, is awful. It’s usually a sign something is wrong. Such a smell in your kitchen, bathroom, or laundry room may come from the sewer or point to a broader issue. Fortunately, you can do something about the sewer smell in your house.

While you shouldn’t ignore unusual sewer smells, the most challenging part of handling it is determining where the smell comes from. Most people assume it comes from the toilet, but sewer smells can also hide in your home’s plumbing system. Here are the top sources of sewer smell in your home, so you can quickly get your house back to its fresh scent. 

Toilet Wax Ring 

The toilet wax ring creates a water and airtight seal between your drain pipe and the toilet bowl base. Over time, the wax ring deteriorates, drying up or breaking down. The seal cracks, causing the small space between your toilet and the wax ring to release sewer gas from the drain beneath your toilet. If the wax ring is causing the sewer smell, your toilet may feel wobbly, may become slightly slanted, or leak water around the base. 

Improperly Cut or Installed Vent Pipe

The plumbing vents in your home travel through the walls and up through the roof. The vent pipe regulates your plumbing system’s air pressure and redirects odors outside your home, preventing leaks in the home. Improperly placed vent pipes can cause leaks in the plumbing system, allowing sewer gas to enter your home. A cracked vent pipe can allow odors into your home through the walls near your toilet. Sewer gas can also leak if your vents are too close to a window.

Water Traps

P-traps are winding U-shaped pipes that hold water below every drain in the house. When these pipes are working correctly, P-traps hold enough water, creating a natural barrier that prevents sewer gases and odors from getting into your home. If you don’t use the shower often, the water in the trap can dry up. If you notice a sewer smell from your drain, despite frequently using the shower, it could be a leaking P-trap preventing it from holding water.

Clogged Drains

Drains transport toxic waste through your home’s septic system. A clogged drain is one common cause of sewage smells. Water backing up in your bathtub or when you flush a toilet signals your sewer drain line is clogged. A clog in the drainpipe causes sewage backup and a buildup of organic matter like soap and hair. If not addressed, bacteria forms on the clog and continues to build up, releasing a foul odor that resembles a sewage smell.

Why Does My House Smell Like Sewer When It Rains

Biofilm Accumulation

A smelly shower drain may be because of biofilm accumulation. Most people use products such as shampoo, shaving cream, body oils, conditioner, and soap as part of their daily hygiene routine. These products wash down the drain accompanied by natural debris such as hair and skin cells. Over time, they accumulate along the P-trap and other pipes underneath your shower, producing biofilm. When biofilm builds up, it releases a sewage smell.

Why Does My House Smell Like Sewer When It Rains?

In most places, rain is needed and welcomed. It cleans the air and helps things grow, but it can cause problems with your home. These issues will make your home smell like a sewer when it rains.

Septic Systems

Septic systems can fail when you neglect maintenance or tree roots cause issues. A broken pipe or crack in the sewer line cause your septic tank to fill up with rainwater, forcing sewer gas to rise and the space around your house to smell bad. 

Rain also causes atmospheric pressure changes, so methane gases in the septic tank don’t flow through the vent normally, producing a foul smell. A septic tank with a blocked venting system or a full septic tank are other potential causes of sewer smell.

Bacteria and Decomposing Waste

Most sewers are composed of a mixture of human waste, moisture, and drainage, which can produce a terrible smell. Decomposing waste and bacteria in the sewer system can produce a sewer smell in your house. The bacteria emit a sticky substance that helps them cling to the side of pipes and continue building up.

Water Pressure

When it rains, because of gravity, rainwater runoff usually goes to the lowest point possible. Typically, it will pour into any available pipe or break into your septic tank. To accommodate the increasing volume, the water pushes the sewer gas to move upward. Since the fumes have a lower density, they are forced out of sewers, producing a bad smell.

Why Does My House Smell Like Sewer in the Winter?

Why Does My House Smell Like Sewer in the Winter

Cold temperatures may cause downdrafts from building plumbing vent stacks. If the weather is windy, you’ll notice the odor varies throughout the day. If the odor subsides as the temperatures rises, downdrafts are to blame for the sewer smell in your house. 

The cold winter weather can cause the drain field to freeze solid. This makes the septic system back up, pushing sewage back into your home long before there’s a real sewage backup. A blocked septic tank line, clogged waste line, or failed drain field, forces drains to back up, starting with the lowest drain.

How to Find Sewer Smell in House

A sewer-odor detection test also known as a smoke test is the best way to identify the source of sewer smells in your house. It’s a process that involves blowing colored smoke into the sewer line. The plumber blocks off the drain line with a test ball and traps the smoke inside your plumbing system. The smoke will flow through the plumbing system and appear in the point allowing the sewer smell into your home.

What Causes Sewage Smell in a Bathroom?

These are the top 3 reasons for a sewer smell in your bathroom:

A Loose or Broken Seal

Your toilet attaches to the drain through two separate seals. When these are broken, loose, or improperly installed, sewer smells can enter your bathroom. A toilet bowl that doesn’t fill up normally is one sign that your toilet has a broken seal. Your toilet may also be broken, or have cracks around the bolts fastening it to the floor. These cracks can allow sewer gas to seep into your bathroom.

Bacteria in Your Plumbing System and Water Heater

A bad sewage smell may also stem from bacteria attracted by water pooling in crevices in and around your toilet. As these bacteria grow, they emit an offensive odor. If the sewer smell is only present when you use hot water, your water heater is the issue. If you leave the heater turned off for long periods or the temperature is too low, bacteria colonies can build in it. They are not dangerous, but they can create a powerful horrible smell, making it harder to take a shower.

Buildup in the Overflow

Your bathroom sink overflow mechanism can also cause a bad sewer smell in the bathroom. Most sinks are designed with a hole near the top to act as a water outlet, preventing overflows into the bathroom. However, with continued use, your sink can build up mildew and grime quickly, mainly in the overflow area. 

How to Get Rid of Sewer Smell

How to Get Rid of Sewer Smell

A sewer smell is unmistakable. Smelling it in your home is unpleasant and with continued exposure, it can be harmful to your health. Once you’ve identified the source of the smell, here’s how you can eliminate it: 

  • Get an experienced plumber to diagnose the problem with improperly installed or cut vent pipe and reinstall a new one.
  • Replace the wax ring around the flange
  • Let the water run for a few minutes to fill up the water trap and restore the seal. Alternatively, flush water down the drain often.
  • Pour antifreeze into drains, then cap them to prevent water from freezing as temperatures drop. Cover your toilet with saran wrap to stop water from evaporating. 
  • Use a drain snake to clear out clogs in the drain line or contact a professional plumber to examine your drain
  • Clean biofilm with a mixture of boiling water, baking soda, and white distilled vinegar.
  • Check that your toilet drain is not loose. 
  • Apply some fresh caulk to fix a loose or broken seal
  • Clean the sink overflow with bleach, water, and a small bottle brush.

Is Smelling Sewage Harmful?

Sewer gas is a mixture of toxic and non-toxic gases that come from decaying waste in your sewer system. Residential sewer lines contain regular gases such as oxygen, carbon dioxide, and nitrogen. They may also include toxic gases like ammonia, hydrogen sulfide, carbon monoxide, methane, sulfur dioxide and nitrogen oxides. 

At low levels, sewer gas isn’t toxic. But with high-level exposure or exposure over a long time, the sewer smell can negatively affect your health. You may develop headaches, fatigue, memory loss, nausea, respiratory problems, poisoning, loss of coordination, asphyxiation, and dizziness. Also, methane and hydrogen sulfide are highly flammable substances, which increases the risk of fire or explosion.

There are many reasons why your house may be smelling like a sewer. While identifying them is the most challenging part, solving them can also be equally hard. Know when to apply DIY techniques and when to call a plumber to avoid making the issue worse. 

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