Exposure to sewer gas isn’t a pretty experience due to the accompanying foul odor. More dangerous are the health risks presented. Sewer gas poisoning is real and can be deadly when inhaled in significant amounts.

Sewer gas poisoning usually happens when a sewer system is faulty.

You could also be exposed to sewer gas when you don’t put on a protective gas mask. This results in direct inhalation of harmful gases, thus leading to poisoning.

Let’s begin our discussion by first understanding what sewer gas consists of.

What Are Sewer Gases?

The term “gases” is used to indicate the plurality of gases produced by a sewer system.

The primary constituents of sewer gas include hydrogen sulfide, methane, ammonia, and carbon dioxide. Carbon monoxide among other gases is found in trace amounts.

  • Hydrogen Sulfide

Hydrogen sulfide is the most dominant septic gas contained in sewer systems. Based on the focus of our discussion, exposure to this gas presents significant health risks.

However, the level of risk depends on how long and the volume being inhaled.

Hydrogen sulfide can be identified by its rotten egg-like smell which is very awful. Though unpleasant, it gives you a heads-up when you begin to perceive it.

In other words, you’re able to find the causes of such sewer gas leaks and have such issues fixed. You also get to stay out of the area.

  • Methane & Carbon Dioxide

This is another gas that gets released from a sewer. As greenhouse gases, no major health risk is presented.

However, methane is known for its highly flammable nature. Therefore, exposure to large amounts of methane could result in a fire whenever you light a matchstick or put on a lighter.

  • Ammonia

Ammonia gas is also released from a sewer and poses significant health risks as hydrogen sulfide. This is found in measured amounts in certain cleaning products.

However, major exposure to ammonia could lead to severe health risks.

Such risks include organ damage and possible death. At lower volumes, exposure may result in eye, nose, and throat irritations. These are real issues you have to be careful with.

About Sewer Gas Leaks

Onsite sewage treatments are usually ideal for persons not close to central sewer systems.

Homeowners tend to have more responsibilities maintaining their sewage systems compared to those hooked up to central sewer systems. Now, there are possibilities for malfunction.

One area of malfunction has to do with sewage gas leaks.

These are very awful smells that could make the air around your home uncomfortable to breathe. So, apart from such gases smelling awful, do they pose any harm?

This is what we’ll be discussing. Here, you’ll find all the answers relating to safety.

Breathing in Sewage Gas is Harmful

It’s evident from our discussion so far that sewer gases are indeed harmful.

Apart from smelling awful, such gases can pose significant health risks when inhaled in sufficient quantities. The odor you perceive mostly comes from one of these gases; hydrogen sulfide.

Not only does hydrogen sulfide smell awful, but it’s also toxic. Such toxicity arises from its effect on the central nervous system as well as the respiratory system.

When inhaled in sufficient amounts, hydrogen sulfide will hurt the skin as well as mucous membranes.

This gas has a characteristic rotten-egg smell. It’s corrosive, flammable, and colorless. As a matter of fact, its toxicity is second only to carbon monoxide in terms of inhalation-related deaths.

Due to its potential for being fatal, you should avoid it as much as you can.

Another toxic sewage gas is ammonia. Like hydrogen sulfide, it’s harmful when exposed to significant levels for a considerable period of time.

  • Consider the Awful Smell as a Warning Sign

Although hydrogen sulfide gases smell awful, leaks serve as vital warnings that must be addressed immediately.

Other component sewage gases are odorless. So, you must be able to identify the smell and take precautionary steps to enhance your safety.

  • Concentration Levels are Vital

For sewer gases to be considered a risk, the concentration levels must be unsafe.

Ordinarily, sewage gases are channeled out through the vent. These escape points are components of the sewage system and extend to the roof.

This way, they escape without posing any harm.

However, during a leak, such gases may become toxic especially when inhaled in higher concentrations.

Several symptoms may show ranging from fatigue, headaches, nausea, or vomiting as well as dizziness or lightheadedness.

You may also experience poor concentration. These symptoms are often common at low concentrations.

At high concentrations, the symptoms tend to be more severe. Exposure to sewage gases at high levels could result in irritation of the lungs, throat, and mouth as well as loss of smell.

With the loss of smell, you are unable to perceive the characteristic rotten egg smell. Other symptoms that may result include seizures, eye irritation, and pink eye, coma, and even death.

This explains why it’s important to immediately have an expert investigate sewage gas leaks to resolve such.

  • Length of Exposure is Crucial

Apart from concentration levels, the length of exposure to sewage gas also matters.

All the symptoms discussed above aren’t experienced immediately during exposure. Prolonged exposure typically leads to these symptoms.

It’s important when perceiving sewage gases to have the problem addressed.

Keeping yourself away from prolonged exposure is also important. If the smell is coming from within your home, it’s best to move out until it’s resolved.

When it’s mostly outdoors, consider staying off the smelly area until it’s resolved.

The Sewage Gas Poisoning Effect

In the previous section, we considered the individual gases released or produced by a sewer system.

All such gases combined are far more potent and deadly. That is what makes sewer gas poisoning a major health risk that needs to be given all the attention it deserves.

The whole process of poisoning begins with exposure. The level of exposure will determine its severity. Sewer gas is supposed to be channeled out through gas vent provisions. However, problems may develop along the way.

You may be faced with a malfunctioning gas vent. Sewer gas leaks may also result. All these are real issues that cause problems.

There are two types of symptoms; mild and severe.

  • Mild Symptoms of Sewer Gas Poisoning

When exposed to sewer gas, you’re likely to notice certain symptoms.

These include headaches, fatigue, lightheadedness, or dizziness as well as vomiting or nausea. Poor memory and concentration are also a possibility. These symptoms are what you’ll experience with mild exposure.

  • Severe Symptoms of Sewer Gas Poisoning

Severe exposure to sewer gas is possible in industrial settings and is quite deadly.

Symptoms are much more serious than mild exposure. You’re likely to experience a loss of smell. When this happens, even the strong awful odor of hydrogen sulfide isn’t perceived.

Other severe symptoms include lung, mouth, and throat irritation caused by ammonia gas, pink eyes, and eye irritation as well as seizures. The worst of these include coma and possible death. This speaks volumes about the risk posed by sewer gas poisoning.

You’ll need to completely avoid situations that expose you to such gases.

Detecting Sewer Gas Leaks

Luckily, it’s easy to detect sewer gas leaks. Such leaks can be easily picked due to the awful odor being released. The most noticeable smell is that of hydrogen sulfide with its rotten egg smell.

When this is noticed, you’ll need to immediately swing into action.

Response to Sewer Gas Poisoning

Most times these gas leakages aren’t as severe. However, the longer you leave the problem attended to, the worse it becomes. The most appropriate response to mild sewer gas exposure is to aerate your home.

This includes opening up your windows and putting on a fan to keep out these gases.

The next important step to take is to call your plumber immediately. The professional plumber comes around to detect the leak source and have it fixed on time.

However, the approach is much different, and rightfully so for severe sewer gas poisoning scenarios. The most immediate action to consider is to get away as fast as you can from the spot in a bid to inhale fresh air.

Next, seek urgent medical attention or care. So, what are the symptoms of sewer gas poisoning? For the sake of emphasis, the first signs you’ll notice include difficulty in breathing.

Others include dizziness and nausea. Getting medical attention prevents a worsening of the situation.

Never Fix Sewer Gas Leaks Yourself

It’s critically important that you don’t attempt to fix sewer gas leaks yourself.

There are cases of people that have put themselves in harm’s way by attempting to fix sewer gas leaks. Qualified technicians are better trained for such jobs.

When faced with this situation, immediately place a call to your plumber. As you wait for their arrival, move away from affected areas. Affected areas will be those giving off sewer gas odors.

Another action to take has been mentioned earlier; the aeration of your surroundings.

What Causes Sewage Gas Leaks?

Ordinarily, you shouldn’t perceive sewage gases because these are channeled out through the vent on your roof.

So, perceiving such smells is a clear anomaly that needs to be investigated and fixed. Several reasons can be given as to why you perceive sewage gas smells.

These range from a dry trap, a damaged or plugged vent, damaged trap, damaged drain line, clogged drain, loose toilets, and improperly placed vents.

  • Dry Trap

Dry traps often arise from infrequent usage of a drain line. Here, the water that serves to block out sewage gases from escaping gets dried. With a dried trap comes steady gas leaks.

Fixing this problem is quite easy. One or more flushes should be enough to resolve it.

  • Damaged or Plugged Vent

Apart from serving as a path of escape for sewage gases, vent pipes also help equalize pressure differences during flushes. When the vent gets clogged, all of these functions are affected.

The gases will then find any other opening to escape or leak out.

  • Damaged Trap

Water won’t stay in a cracked trap.

This creates a problem as it creates an opening through which sewage gases will escape. Until the trap is fixed or replaced, harmful sewage gas exposure will always be a possibility.

  • Damaged Drain Line

Drain lines may get damaged at some point with use.

Apart from sewage leaks, gases are also likely to exit from this opening. The only option is to have it fixed as soon as possible.

  • Clogged Drain

Clogging issues are common with the misuse of sewage systems.

With such clogging comes sewage backup. This leads to a decomposition of waste which releases sewage gases directly into your home.

  • Loose Toilets

Toilets may get dislodged from points connected to sewer lines. With a loosened toilet, the chances of sewage gas leaks resulting are high.

  • Improperly Placed Vents

Vents not properly installed pose significant risks.

This is seen when such vents aren’t extended to the roof but terminate close to the window. Instead of the gases escaping up, they leak into your home through the opening (window).

Have a Pro Fix the Main Cause(s) of Sewage Gas Leaks

To protect yourself and household members from sewage gas exposure, it’s necessary to have a plumber address any faults causing leaks of these harmful gases.

Breathing in sewage gas is very harmful and should be avoided by all means. The most comprehensive way of resolving the problem is by looking at the possible root causes and have such issues addressed.


Sewer gas poisoning isn’t an isolated event. It’s caused by a malfunctioning sewer system. Such malfunctions may include leaks, blocked air vents, cracked pipes, dry plumbing, clogged drains, and loose toilets.

All of these are possible system malfunctions that will need to be first determined before appropriate action is taken. Your sewer gas leak situation may be caused by one or a number of these situations.

Have these inspected and fixed as early as possible to avoid problems.

Sewer gas poisoning is a problem that can be avoided by taking precautionary actions. This includes proper maintenance of your system.

One Comment

  1. Dee Durden says:

    We’re having problems with bad smells.

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