How To Fix A Sewer Smell In Your Basement

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    Is there a sewer smell in your basement creeping up the stains and making the rest of your house smell like sewer gas? Sewer smells can be quite unpleasant – and can be caused by a number of things in your plumbing.

    In this article our team of plumbing experts will show you how to keep your basement from giving off a sewage smell. We will show you how to check the vent pipe, floor drain, sump pump, sump pit, sewer line, septic tank and shower drain (if you have one in your basement) and keep the nasty sewer gas smell from leaving the sewer line.

    Removing Smells with Cleaners


    Your normal household bleach can go a long way in removing drain smells. Mix a few caps of bleach with 1 gallon water and pour down the drain!

    How to Get Rid of Sewer Smell in Basement

    Getting rid of a basement sewer odor is easy – any you probably won’t have to call a professional plumber. Follow these step by step instructions and your home should be back to smelling normal in no time.

    1. Locate the smell – The first step in removing the sewer smell is to find where it is coming from. Start by using your nose and finding where the smell is strongest.
    2. Refill the water trap – Next check the water trap and refill it with fresh water plus a tablespoon of bleach and cooking oil (which helps with evaporation)
    3. Clean the cleanout plug – Cleanout plugs are another source of foul odors. Give you plug a cleaning and retighten it to make sure it is air tight.
    4. Check the wax ring seal – If your basement has a toilet the problem could be with the wax ring seal and toilet flange. Make sure this is not leaking or you may need to recaulk.
    5. Inspect for broken pipes – Broken pipes can cause water damage – and a serious stink. Check for a broken and cracked drain pipe by looking for pooling water and damp spots near the floorboards.
    6. Light a candle – If the smell still lingers try lighting a candle and cracking open a basement window well to increase the airflow

    What Causes Sewer Gas Smells In The Basement

    There are a few common causes of sewer smells in your basement – and most have easy fixes to prevent a rotten egg smell and unpleasant odor!

    The most common source of basement sewer smells is a dried-up drain. Basement floor drains use a trap that contains a small amount of water to hold smells inside the sewer lines. If the trap dries out smells will creep up into the basement and eventually into the rest of this house.

    Another common cause of basement odor is problems with your sump pump, ejector pump, basement toilet, water heater or vents. Perform a routine maintenance check of each of these pieces of equipment – if the smell of rotten eggs and hydrogen sulfide gets stronger you may have found the problem!

    Sewer Grates and Cleanout Plugs

    Make sure to check the grate and cleanout plug. If that plug has been removed gas will flow directly into your home

    Sewer Gas Smells When It Rains

    When it rains it is not uncommon for sewer gas to creep out of the floor drain and cause the house to smell. This is caused by a change in air pressure causes the air to become heavy and fall – and the sewage smell rises from the drain pipe to takes its place!

    An unpleasant rotten egg smell can also come from your sewer system after a large rainstorm due to the unpleasant odor of sewage gas being forced upwards by water being pulled down the lines by gravity!

    Rain can also cause organic matter that is decomposing in the pipes to release additional odors – as long as you have a u-shaped sewer trap with a water trap you will be able to keep the sewer gas odor in the pipes. Plus – many homeowners insurance policies require a working water trap and drain line for full coverage!

    Sewer Smells During Cold Weather and Winter Months

    Sewage smells are likely to increase in cold weather and winter months for a number of reasons. Ice can crack drain lines and cause a sewer odor to rise from the plumbing vent and into the rest of the home.

    Another problem is in winter months is small animals making a home in the sewer pipe – which blocks the line and causes a foul odor to climb into the home.

    Frozen systems add another layer of problems – all of which can cause sewer gas to enter your basement. Frozen lines can break – and clog – which can require full replacement of the sewer system – or just defrosting if possible if you don’t want your a basement smell and water damage.

    Is a Sewer Smell in the House Dangerous?

    While hydrogen sulfide is toxic to humans – the amount that enters your home from the drains is not enough to cause any problems. Levels of hydrogen sulfide gas need to reach at least 150 ppm – which is fall lower than the amount creeping up from the ejector pit in your basement.

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