When organic waste decomposes, they give off gasses, many of which are poisonous when inhaled by humans. Whether you have a septic or sewage system for the removal of waste from your home or property, these gasses (commonly known as sewer gas) are typically produced and emitted in large quantities from these systems. When anyone is exposed to either small or large amounts of sewer gasses, it could lead to serious health issues, and even death sometimes. This is why sewer gas detectors are important.

Although homeowners are at risk of exposure to sewer gasses, sewer and drain contractors and personnel who work on sewer and drain systems are the most at risk of exposure to sewer gasses. In many cases, they work in confined spaces, which are often filled with decomposing waste that emits hazardous gas. For this reason, they use sewer gas detectors to monitor the presence and levels of poisonous gasses when working on sewer systems. 


What is a Sewer Gas?

Like the name implies, sewer gas is the type of gas emitted from sewer systems. Several gasses are categorized as sewer gasses. The most common ones are Hydrogen Sulphide (H2S) and Methane (CH4), both of which are given off by waste as they begin to decompose. Both CH4 and H2S are toxic and highly flammable gasses. H2S is highly particularly poisonous and can cause death within minutes of exposure to it. 

Exposure to concentrations as low as 10ppm can cause a severe impact on anyone. In confined space environments where there is a limited supply of oxygen, Hydrogen Sulphide (H2S) and Methane (CH4) can explode very quickly. But aside from H2S and CH4, there are other gasses that are categorized as sewer gas. Examples include carbon monoxide (CO), carbon dioxide, (CO2), and ammonia. These are present in lesser quantities but are also hazardous when individuals are exposed to high levels. 

CO, in particular, is a notoriously poisonous gas, though not commonly regarded as sewer gas, but is not uncommon around sewer systems. Note that there is a constant presence of about 21% oxygen in the air, but due to limited ventilation in confined spaces, sewer and drain specialists or even residents conducting DIYs, may be exposed to dangerous amounts of CO, even as oxygen (O2) is replaced by CO2 when we breathe. 

This is exactly why it is important to use systems that can detect and monitor possible exposure to harmful gas when working in confined spaces or on sewer systems. Aside from this, installing a sewer gas detector can help save lives when leakage occurs. In other words, they serve as alarms to tell you that a hazardous gas is in circulation, even before anyone inhales it. See the next section for details on how a sewer gas detector works.


How Does a Sewer Gas Detector Work?

As stated earlier, a sewer gas detector alarms you of the possibility of sewer gas presence around you. It shows you the kind of gas that has been detected. Some sewer gas detectors can only detect one or two types of sewer gasses. 

However, standard and reliable sewer gas detectors are designed to detect all major sewer gasses, such as hydrogen sulfide, ammonia, carbon dioxide, methane, and carbon monoxide. Such sewer gas detectors are called multi-meter detectors, as they can identify the presence of multiple sewer gasses. 

These detectors use different technologies to pick up the presence of these poisonous gasses. Some use infrared sensors. Others use electrochemical sensors or catalytic sensors. Detectors that use infrared sensors work by detecting infrared light beams emitted by gasses around the sewer system. 

Electrochemical sensors detect sewer gas presence by measuring electrical currents generated when sewer gasses interact with specific chemicals. Regardless of the type of sensors in use, a sewer gas detector triggers an alarm when it detects the presence of sewer gas presence. They are often hand-held devices, but can also be carried on the body or installed on certain parts of the building.

Sewer gas detectors also provide clear visual indicators, alongside audible alarms to tell you when a sewer gas has been detected in your environment.

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Common Causes of Sewer Gas Smell

Sometimes, in your home, you may notice a sewage gas smell or a foul odor emanating from your sink or bathroom. There are some normal or common reasons why this may happen in certain parts of your home, and in most cases, you can get them fixed easily.

Water Traps: Water traps (also known as P-traps or S-traps) are usually found close to floor drains and laundry tubs, underneath your sinks. They typically have a curved shape, which traps water and helps to block the gas from traveling back into the house. But water traps do dry out over time, especially when they haven’t been used for a long time, and this lets the sewer gas into the house. This can also happen when there is a leak somewhere before the trap. 

To correct this, you can simply run water from the sink for a few seconds to restore the trap, and if the smell is emanating from a floor drain, pour some water down the drain to eliminate the smell.

Other common reasons why you might experience sewer gas smell in your home are: 

  • Missing clean-out plugs
  • Sewer and septic line leaks (you should call a professional for this)
  • Loose connections along the vent pipe or sewer line


What Can You Do When You Notice a Sewer Gas Leak?

If the sewer gas leak is from your sink or floor drain, allowing water to run through the sink or drain can often help to restore proper function. But if the smell persists or comes from a different part of your house, such as the sewer line or septic tank leak, the first thing to do is to evacuate the area. 

Remember that sewer gasses are poisonous and prolonged exposure to them is detrimental to your health. A sewer gas detector only points you to a problem, so you need to leave the environment and call an experienced sewer and drain specialist to examine the situation and fix the problem.

At N.W. Sewer & Drain, we have a team of trained and ready sewer and drain specialists to handle every drain issue you have. We can also help you purchase and install an effective sewer gas detector at strategic places in your home or commercial property. Have more questions? Feel free to reach out to us today at 206-931-7728 to speak with one of our experts.

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