A woman holding her nose due to a bad smell.

Is Sewer Gas Dangerous?

When we think of sewers, we often imagine them as dark, damp, and smelly places. Sewer gas is what causes that pungent odor, and exposure to it can be a cause for concern. But is sewer gas dangerous? The short answer is yes, sewer gas is harmful to your health in some instances, and exposure to it should not be taken lightly.

What Is Sewer Gas?

Sewer gas is a mixture of several different gases that occur naturally in the environment. The gas is generated by the breakdown of organic materials, such as human waste and food residue, in the sewer lines. It’s composed of a variety of gases, including methane, carbon dioxide, hydrogen sulfide, ammonia, and even trace amounts of carbon monoxide. All of these components can be toxic to the oxygen systems and can lead to numerous health issues.

So, why is sewer gas dangerous? Let’s go over everything you need to know in more detail below.

Why Is Sewer Gas Harmful?

Exposure to sewer gas leaks can produce a range of symptoms that can vary from unpleasant to life-threatening. The symptoms of sewer gas exposure are similar to those of a cold or flu and can include headache, nausea, eye irritation, and a sense of dizziness or weakness. In some cases, exposure to high amounts of sewer gas can be fatal.


Sewer gas is dangerous when present in high levels — and one of its more toxic components is ammonia. Ammonia can be harmful to humans, even at low levels. Prolonged exposure to high levels of ammonia can cause respiratory, skin, and eye irritation, even leading to serious health problems. People who work in environments where ammonia is used, such as fertilizer plants and other industrial settings, are at a higher risk of developing health problems caused by exposure to the gas.

Hydrogen Sulfide

Another gas found in sewer gas is hydrogen sulfide, which is responsible for the characteristic rotten egg smell. Hydrogen sulfide is extremely toxic to living organisms and can cause death in high enough concentrations. Exposure to low levels of hydrogen sulfide can cause eye and lung irritation, while exposure to high levels of the gas can cause rapid breathing, fatigue, irritability, and, in some cases, coma and death. As you can see, it’s easy to understand why sewer gas is harmful in some instances.

Preventing Exposure to Sewer Gas

Although sewer gas is dangerous, preventing exposure to it is relatively easy. The most effective way to prevent sewer gas from entering your home is to ensure that it’s properly ventilated. Make sure that all your plumbing fixtures, including sinks, toilets, and showers, have proper venting. In addition, make sure that all plumbing traps, such as those in sinks, are properly sealed to prevent sewer gas from entering your home.

Contact Our Plumbing Experts Today

It’s clear that sewer gas is harmful when present at dangerous levels and is not something to be taken lightly. In high concentrations, it can be toxic and can cause serious health problems. If you notice a rotten egg smell in your home, it’s essential to take it seriously and call a professional plumber to inspect your plumbing system. Though it may be intimidating to think about, raising awareness about the dangers of sewer gas is essential to keep ourselves and our loved ones safe.

If you need a 24-hr emergency plumber, turn to the experts at Magnolia. We can help with all of your needs to keep your plumbing and sewer systems in top condition, whether you need a quick repair or sewer and drain cleaning services in Washington, DC. Contact us today to request an appointment!