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What is Sewer Gas?

Marjorie McAtee
Marjorie McAtee

Sewer gas is a mixture of various gases that can form when household waste or other waste decomposes. Some of the gases that typically make up sewer gas, such as ammonia and hydrogen sulfide, are dangerously toxic. Sewer gas can accumulate in septic tanks, municipal sewers, and manure tanks. Sometimes, it can leak into the home through blocked or leaking drains, vents, and sewage pipes. When sewer gas contaminates the inside air of a home, it can present a number of health risks, and can even be fatal in large amounts.

The mixture of gases commonly known as sewer gas is usually a by-product of industrial or human waste decay. Hydrogen sulfide and ammonia may be the most toxic gases present in any given sewer area. Other gases that can occur as a by-product of waste decay include carbon dioxide, nitrous oxide, methane, and sulfur dioxide. Industrial waste may produce gaseous by-products such as chlorine during decomposition.

Sewer gas can accumulate in septic tanks.
Sewer gas can accumulate in septic tanks.

Exposure to toxic gas can cause a range of health problems and can even be fatal. Small amounts of sewer gas in indoor air can cause irritation of the eyes, sore throat, cough, and pulmonary edema. Low appetite, headaches, fatigue, dizziness, memory problems, and irritability may occur in those exposed to low levels of these gases for a longer period. Strong concentrations of this gas can lead to unconsciousness and eventually prove fatal.

Exposure to toxic gas can cause memory problems, headaches, and irritability.
Exposure to toxic gas can cause memory problems, headaches, and irritability.

Sewer gas can generally be identified by its smell, which is said to be reminiscent of rotten eggs. Strong concentrations of these gases can, however, impair the sense of smell, making the stench of the gases impossible to detect. These gases are also generally extremely flammable.

Those who work in maintaining and cleaning sewers, septic tanks, or manure tanks may be most likely to be exposed to dangerous gas. This mixture of gases can leak into the indoor air of a home if the home's plumbing pipes, drains, and vents are poorly maintained.

Some who work with sewer gases may be required to wear personal protective equipment.
Some who work with sewer gases may be required to wear personal protective equipment.

Most homes have plumbing vents on the roof that allow gas to escape from the home's plumbing system. Keeping these vents clear can help keep sewer gas from leaking into the home. Properly maintaining and cleaning drains and pipes within the home can also stop the leakage of dangerous gases.

Homeowners who suspect a sewer gas leak are generally advised not to occupy their homes until the leak is resolved. Public health authorities and local fire departments may need to be notified of the problem. A professional plumber can usually be contracted to resolve the situation.

Frequently Asked Questions

What is sewer gas and what are its main components?

Sewer gas can cause eye irritation.
Sewer gas can cause eye irritation.

Sewer gas is a complex mixture of toxic and non-toxic gases produced during the decomposition of organic household or industrial waste. The main components typically include hydrogen sulfide, ammonia, methane, carbon dioxide, sulfur dioxide, and nitrogen oxides. Hydrogen sulfide, with its distinctive rotten egg smell, is often the most noticeable component.

Is sewer gas dangerous to human health?

Breathing in small amounts of sewer gas may cause a sore throat, among other symptoms.
Breathing in small amounts of sewer gas may cause a sore throat, among other symptoms.

Yes, sewer gas can be dangerous to human health, particularly at high concentrations. Exposure to low levels can cause irritation of the eyes, throat, and lungs, as well as headaches and dizziness. High levels of hydrogen sulfide, a primary component of sewer gas, can be fatal, as it interferes with cellular respiration and nervous system function.

How can sewer gas enter a home or building?

Sewer gas can enter a home or building through dry traps in plumbing fixtures, cracks in the foundation or plumbing pipes, and improperly installed or maintained vent pipes. It's essential to ensure that all plumbing fixtures are used regularly to keep water seals intact and that vent pipes are free of obstructions.

What are the signs of a sewer gas leak?

Signs of a sewer gas leak include the presence of a foul, rotten egg odor, which indicates hydrogen sulfide. Other signs may include frequent headaches or dizziness among occupants, and bubbles in toilets or drains, which suggest a breach in the plumbing system. Persistent symptoms or odors should be investigated promptly.

How can I prevent sewer gas exposure in my home?

To prevent sewer gas exposure, regularly maintain your home's plumbing system. This includes pouring water down infrequently used drains to maintain trap seals, fixing any cracks or leaks in pipes, and ensuring proper ventilation of sewer gases through vent pipes. Annual inspections by a professional can also help identify potential issues early.

What should I do if I suspect a sewer gas leak?

If you suspect a sewer gas leak, immediately ventilate the area by opening windows and doors. Avoid igniting any flames or operating electrical switches, as some sewer gases are flammable. Contact a licensed plumber or your local health department to investigate and resolve the issue as sewer gas can pose significant health risks.

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    • Sewer gas can accumulate in septic tanks.
      By: gozzoli
      Sewer gas can accumulate in septic tanks.
    • Exposure to toxic gas can cause memory problems, headaches, and irritability.
      By: pressmaster
      Exposure to toxic gas can cause memory problems, headaches, and irritability.
    • Some who work with sewer gases may be required to wear personal protective equipment.
      By: Destonian
      Some who work with sewer gases may be required to wear personal protective equipment.
    • Sewer gas can cause eye irritation.
      By: schankz
      Sewer gas can cause eye irritation.
    • Breathing in small amounts of sewer gas may cause a sore throat, among other symptoms.
      By: Grafvision
      Breathing in small amounts of sewer gas may cause a sore throat, among other symptoms.