How to test for sewer gas in house?

Author: scraper  |  Last update: Wednesday, August 26, 2026

Testing for sewer gas primarily involves identifying the source of the distinct "rotten egg" (hydrogen sulfide) odor. You can easily troubleshoot this yourself by checking for dry P-traps, loose toilet wax rings, and clogged roof vents, or by using a handheld gas detector or a smoke test.

How do you detect sewer gas in your home?

The first thing is to make sure the smell is sewer gas which is usually a rotten egg smell and not a natural gas smell which usually smells like a skunk.

What are the symptoms of sewer gas sickness?

Sewer gas sickness is primarily caused by inhaling toxic compounds like hydrogen sulfide, ammonia, and methane. Symptoms range from mild irritation to life-threatening emergencies, depending on the concentration of the gas and length of exposure.

Is it safe to sleep in a house with sewer gas?

Yes, a sewer gas leak in your home can cause a host of issues, including eye irritation, coughing, wheezing, nausea, vomiting, migraines, drowsiness, and even loss of consciousness.

What is the main cause of sewer gas in a home?

Sewer gas usually enters a house when plumbing drain traps (the U- or P-shaped pipes under sinks, showers, and toilets) dry out, lose their water barrier, or become damaged, allowing foul gases to bypass the system.

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When to worry about sewer gas?

If the smell doesn't go away after basic troubleshooting, or if it comes back regularly, it's time to call in a licensed plumber. Sewer gas can leak into your home due to cracked pipes, faulty vents, clogged drains, or problems in the sewer line.

Is it safe to stay in a house with sewage smell?

Sewer gas contains hydrogen sulfide, methane, ammonia, and other compounds that can cause headaches, nausea, dizziness, and respiratory irritation. Prolonged exposure to high concentrations can be toxic. If you smell sewer gas, identify and fix the source promptly and ventilate your home thoroughly.

Does sewer gas go away on its own?

Sewer gas typically does not go away on its own. It is usually a direct sign of a broken plumbing seal, a clogged vent, or a dry P-trap. Leaving it unresolved poses health and explosion risks due to gases like methane and hydrogen sulfide.

Can a carbon monoxide detector detect sewer gas?

No, carbon monoxide detectors won't detect sewer gas directly, but they can sense methane, which is a component of sewer gas. Installing CO detectors near plumbing fixtures or in basements is a good idea to alert you to dangerous levels of methane.

What are the symptoms of sewage sickness?

Sewage sickness refers to illnesses caused by exposure to raw sewage, which is loaded with harmful bacteria, viruses, and parasites. The most common symptoms include severe diarrhea, vomiting, nausea, fever, abdominal cramps, and headache. Severity depends on how you were exposed.

How long does sewer gas poisoning last?

Hydrogen sulfide can affect several different systems in the body. Exposure to lower concentrations can cause eye irritation, a sore throat and cough, shortness of breath and fluid in the lungs. These symptoms usually go away in a few weeks after exposure ends.

What are two warning signs of gas poisoning?

Two of the most common warning signs of gas poisoning are dizziness and a dull headache. Because fumes displace oxygen in the blood, they often cause "flu-like" symptoms without a fever, which can rapidly escalate to shortness of breath, nausea, and confusion.

What does sewer gas smell like?

Sewer gas is a noxious mixture of toxic and non-toxic gases. It most distinctly smells like rotten eggs or sulfur, caused by hydrogen sulfide. Depending on the mixture, it can also have a musty, stale, or occasionally garlic-like odor due to other decomposing organic matter.

What are the first signs of sewer gas poisoning?

The first signs of sewer gas exposure are a distinct rotten egg odor and physical irritation. Prolonged or stronger exposure commonly leads to the following early symptoms:

What smell can be mistaken for gas in your house?

4. Rotten eggs. A rotten egg smell is one of the most concerning odors in a home. This unpleasant scent is known to be an indicator of a gas leak, commonly caused by natural gas, propane or hydrogen sulfide.

Is there a device that detects sewer gas?

Yes, there are specialized portable gas detectors designed to pinpoint sewer gas leaks. Because sewer gas contains a mixture of gases—primarily methane, hydrogen sulfide, and ammonia—these detectors use highly sensitive sensors to trace odors back to their source.

What is one of the earliest symptoms of carbon monoxide poisoning?

One of the most common early symptoms of carbon monoxide (CO) poisoning is a headache, often described as dull or persistent. Because CO is odorless and colorless, these early signs are frequently mistaken for the flu or food poisoning.

How to detect where sewer gas is coming from?

To find the source of a sewer gas smell, start by narrowing down where the odor is strongest. The most common culprits are dry P-traps, failing toilet seals, clogged roof vents, or a cracked pipe.

What is the silent killer gas?

Carbon monoxide (CO) is widely known as the "silent killer" because it is a colorless, odorless, and tasteless gas that can cause sudden illness or death. It is produced by incomplete combustion in fuel-burning appliances (furnaces, stoves) and engines. It kills by replacing oxygen in the blood, often causing victims to lose consciousness without realizing they are in danger.

What neutralizes sewer gas?

To eliminate sewer gas odors, you can try pouring water down unused drains, checking for plumbing leaks, ensuring proper ventilation, and using sewer gas odor neutralizers or deodorizers.

Does sewer gas get worse at night?

Temperature and air pressure changes at night can make septic tank odors more noticeable. Cooler nighttime temperatures can cause gasses in the septic system to contract, pushing them out through vents or cracks. Lower atmospheric pressure allows gasses to escape more easily, creating a stronger odor.

What is the hardest smell to get rid of in a house?

The hardest smells to eliminate from a house are cigarette smoke, pet urine, and skunk spray. These odors penetrate deep into porous materials (drywall, subfloors, carpets, and air vents), often requiring professional remediation rather than standard cleaning.

Should I call a plumber for a sewer gas smell?

A foul odor is often the first sign of a sewer line backup, but slow drains, gurgling noises, and overflowing toilets and sinks may also indicate a sewer line issue. Don't ignore these signs — turn off the building's water supply and call a professional for sewage backup cleanup.

What is the old lady's smell called?

The characteristic "old age smell" is scientifically known as nonenal (or 2-nonenal). It is a chemical compound produced when the skin's natural oils and fatty acids break down and oxidize as we age.

Can a clogged vent cause sewer gas?

Clogged vents can lead to sewer gas backup, which can make you or your family ill. As people in this region work through one of the coldest winters on record, homeowners should take time to review safety measures to prevent illness from sewer gases.

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