What Causes Sewage Smell in House and How to Get Rid of It

The nostril-assaulting stench of sewage wafting through your house is alarming, to say the least. As we breathe in air, we don’t expect to smell something so nauseating and unpleasant. When those heavy, rotten odors hit your nose, you know you have a serious problem that needs addressing quickly.

Sewage gases contain hydrogen sulfide, the compound that gives rotten eggs their distinctive foul smell. So when you notice that odor, it likely means sewer gases are infiltrating your living space through drains or plumbing pipes. Exposure to hydrogen sulfide gas poses health risks like headache, nausea, and fatigue. But the good news is that once you identify and seal the source, you can eliminate sewage smells for good.

In this guide, we’ll walk through the common causes of sewer gas smells in homes and proven tips for removing the odor permanently. Read on to demystify sewage stench and breathe easy again soon.

What Causes Sewage Smell in House?

The sewage smell in your house is often caused by sewer gas, and it can make your home smell like sewage, which is far from pleasant. Sewer gas is a mixture of gases, including hydrogen sulfide, methane, and ammonia, which can create a noxious odor.

Here are the most common culprits behind sudden sewage smells in homes:

Dried Out or Cracked Sewer Traps

Sinks, tubs, showers, washing machines, and other drains depend on water to form a “trap” sealing sewer gases in the pipe. If the water evaporates over time, it leaves room for gases to escape into the air. Cracked traps also break the seal.

Clogged Vents

Vents extending through the roof allow airflow to prevent vacuum pressure that would suck water out of traps. If they get clogged by nests or debris, gases can back up through drains.

Leaky Wax Ring Under Toilet

The wax ring forms a seal between the toilet drain and the floor flange. If it shrinks or cracks over time, gases can leak out around the base.

Backed Up Main Sewer Line

Tree roots, grease, debris, and other blockages can cause wastewater to back up and allow gases to leak inside through pipes.

Malfunctioning Plumbing Fixtures or Drainage System Parts

Corroded, cracked, or improperly installed fixtures, pipes, valves, joints, or seals can all potentially create openings for sewer gases to leak inside the drainage system and enter living spaces.

Take note if the sewage smell emerges alongside a specific event, like heavy rain. It might point to an exterior drain or main sewer line issue. Now let’s look at the most effective ways to tackle sewer smells at the source.

How to Get Rid of Sewer Gas Smell in House

When sewage stench invades your home, staying on top of hygiene like spraying air freshener and scented candles unfortunately won’t cut it. Masking odors temporarily doesn’t solve the underlying issue.

You’ll need to track down exactly where gases are entering and seal it off. DIY smell removal tactics can work for minor leaks. However severe sewage smells warrant calling a professional plumber to inspect for cracks, clogs, and drainage system issues.

Either way, here are tips for locating the origin and stopping the sewage odor for good:

1. Check Water Levels in Drain Traps

Pour water down seldom-used drains and sinks, then check underneath for leaks. Refill trap water levels if low. Pouring cooking oil or mineral oil instead creates a lasting barrier film.

2. Inspect Visible Pipes and Joints

Scan exposed pipes, valves, fittings, and connections with a flashlight for corrosion and cracks that could release gases into the room. Spray possible leak sites with lemon-scented soap. If bubbles emerge, you’ve located an air leak.

3. Clean Clogged Vents and Drains

Vents blocked by animal nests or plants can cause sewer gas backups. Remove debris with a duct cleaning rod. Flush drains and pour enzyme cleaner to break up organic gunk and grease clogging pipes.

4. Replace the Old Wax Ring Under the Toilet

Worn toilet wax rings allow odors to waft up around the base. Turn off the water, unbolt the toilet, remove the old wax, reseal with new wax, and reinstall toilet.

5. Install a Backflow Prevention Valve

Valves near main sewer lines only allow flow toward the municipal sewer. If wastewater backs up toward your home, the valve seals to block gases.

6. Seal Cracks and Leaks with Epoxy

Apply waterproof epoxy sealant to any identified cracks and leaks around pipe joints, seals, and drains to close off gas escape routes.

7. Install an Air Admittance Valve Under the Sink

The one-way valve allows air into drain pipes to prevent vacuum pressure while blocking gases from escaping.

Persisting sewage smells or large-scale leaks likely indicate bigger drainage system issues. Have a professional plumber snake the main sewer line, pressure test for leaks, survey pipes with a sewer camera, replace corroded sections, or clear roots or blockages.

With some diligent DIY detective work or a plumber’s know-how, you can pinpoint the origin of any unwelcome sewage smells and take the right steps to banish them for good. Don’t tolerate nauseating odors or health risks from hydrogen sulfide gases. Breathe easy again soon using these odor removal and prevention tips.


In conclusion, a sewage smell in your house can be a nuisance, but with proper understanding and preventive measures, you can eliminate it. Regular maintenance, checking for leaks, and ensuring proper ventilation are key steps to keep your home smelling fresh. Remember that if the issue persists, seeking professional help is always a wise choice. Don’t let your house smell like sewage; take action today to enjoy a pleasant living environment.

For sewage cleanup and septic tank pumping around Atlanta, contact Southeast Water Restoration!