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The basement is often the most neglected section of the house. But a strong sewer smell coming from the basement of your house is something you can’t ignore. The odor is not only unpleasant, but it can be dangerous too. Worried about where this smell is coming from? Don’t stress out. The information below will help you identify some of the potential reasons for sewer smell in your basement. You will not only learn about a few causes, but you will also get to know about ways to solve this problem. But first, it is important to know what sewer smell and how is it different from other types of smell.

What is Sewer Smell?

The term “sewer gas” is used to describe a group of gases which result from the breakdown of organic waste in the sewer water. More specifically, sewer gas is a byproduct which is released when human waste breaks down. Sewer gas is often a combination of toxic and non-toxic gases which combine and result in foul odor. The gases which are a part of sewer gas include hydrogen sulfide, ammonia, carbon monoxide, and many other gases.

A few distinguishing things about sewer gas is that it is always a foul smell (similar to the smell of rotten eggs) and if left untreated, it can pose serious risk to your health. Some of the common health concerns caused by sewer smell include headaches, vomiting, and general illness. Though sewer gas can be a health concern when inhaled regularly, primarily it is an unpleasant experience. As soon as you notice sewer smell, you should seek professional assistance as it is a sign of some underlying plumbing issue in your house.

Potential Causes of Sewer Smell in Your Basement

Sewer gas can be an indication of numerous problems with your plumbing fixtures. Some of the potential causes of sewer smell in your basement include:

Dried Floor Drains

Floor drains which are rarely used in the basement of the house are one of the most important sources of sewer smell. Floor drains are usually designed with a trap which holds small amount of water. This acts as a seal which prevents sewer gases to escape into the house. Over time, with little use, the drain dries up which allows sewer smell to release in the house. As a result, you can notice sewer smell in the basement.


If you notice sewer smell in your basement and are not sure about the cause, you can dump a gallon of clean water in the drain. This will reseal the drain and will keep the foul odor out of the basement. You can also add a mild detergent or cleaner to the water for fresh scent. If the smell persists, then you need to contact a professional plumber. Persistent foul smell in your basement can be an indication of some other underlying plumbing problem.

Cleanout Plug

If you notice foul smell in your basement, it is important to check for the cleanout plug inside the floor drain. In some floor drains, there is no cleanout plug. In that case, sewer smell gets a direct path into the basement of your house.


You can check the cleanout plug by removing the grate on drain opening. In case the cleanout plug is missing, you can purchase the new plugs from a hardware store. If you are not sure which plugs to purchase, contact a professional plumber.

Ejector Pump

When plumbing fixtures are located below the level of the main sewer line flowing from the house, you need an ejector pump. The pump must be sealed with a cover and should be vented properly so that it can contain waste water. In case the lid is missing or the seal is broken, sewer smell will surely overwhelm your basement.


If you have an ejector pump, make sure the lid is properly fitted and the seal is intact. Also inspect the pipes which carry waste discharge for any blockages. In case, any component is damaged and needs repair, contact a professional plumber as soon as possible.

Sewer Line

The sewer smell in the basement can also be a result of a damaged sewer line. If this is the cause and the damage or leak in the pipe is close to your home, the waste water can leak into the ground and you will notice it in the sump pump of your basement.


Damaged sewer lines are best handled by professional plumbers. They are trained to identify and repair any leaks in the sewer line.

Inappropriate Vents

Often plumbing fixtures and appliances in the basement do not get vented. As a result, sewer gas accumulates in the area and does not exit from the house.


Ensure that the laundry rooms and bathrooms in the basement and other parts of the house are appropriately vented. This will allow sewer gas to escape out of the basement easily.

If sewer smell is persistent in your basement even when you rule out these culprits, contact a professional plumber for a more detailed inspection.

Professional Plumbing Repair

When you need a quick response from a plumbing company which prioritizes your needs,Mesa Plumbing Company is the company of your choice. We offer specialized services with exceptional quality at an affordable price. Whether you want to schedule an appointment or need emergency services, visit our website or call now at 480-832-1660.

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