Sump Pump Smells: How To Remove Sump Pump Odors

Sometimes a bad sump pump smell is the awakening call that you need to clean and deodorize the sump pump. Keeping it clean is the best way to avoid foul odors from building inside the unit. But what if there is already a bad smell coming from the sump pump? You need to act fast to prevent the odor from growing and eliminate the cause. Here’s everything you should know about it and how to overcome such odors.

sump pump smell

What Does a Sump Pump Smell Like?

There are some foul odors that you will commonly experience with your sump pump. Odors can be identified only by comparing them to a commonly known smell. The following are some of the significant odors that you will detect easily.

  • Sewer gas: This smell might seem like gasoline at first, but grows stronger over time. This contains both toxic and non-toxic gases due to sewer gases passing through the pipes. So, you should watch out if you smell a gaseous odor from your sump pump.
  • Mold and mildew: Mold growth is a common scenario in sump pits that continuously handle water. Try to keep your sump pits dry to avoid moldy smells.
  • Rotten eggs: This usually gives away the sulfur gas coming from the pump. Different forms of dirt buildup will usually cause this odor.
  • Waste: If you smell trash or garbage in your sump pump, it is another effect of clogged debris. Regular cleaning schedules with some bleach will help fix this smell.

What Causes Sump Pump Smells?

Sump pumps work continuously to drain water from the basements during storms. It basically removes the groundwater that seeps into the basement. Amidst its hard work, you might suddenly find that your sump pump smells like sewage. Here are some of the common reasons behind a smelly sump pump.

Sewage Infiltration

Sewage may saturate the groundwater if a sewer line leaks close by. This will cause the sump pump to smell as it collects excess groundwater containing the infiltrated sewage. This may make the sump pump smell continuously if the problem persists. To fix it, you need to call an emergency plumbing service. They will use a camera to inspect the sewer lines and find the location of the leak. Once the necessary repair is done, there will be no more sewage infiltration to cause the sump pump to smell. 

Stagnant Water

Water standing in one place for a long time also creates an odor in sump pumps. The sump pump will remove water only up to a certain level in the basin. There will be even more water in the basin if the float switch is not adjusted properly. A defective check valve can also cause stagnant water in the sump pit. This happens when the water pumped out, flows back when the sump pump stops due to the defective check valve. Since there is water resting in the basin always, it will stagnate causing unpleasant odors over time.

Dry Sump Basin

A sump pit should have a small amount of water always. However, water in the sump pit evaporated during dry and warm seasons. Gases escape when the basin dries completely, which in turn causes bad odors. So, check the sump pit and if it is dry, add some fresh water to cover the drain lines running from the pit.

Basement Drainage

Sometimes the basements are used for bathrooms and laundry rooms. So, the sump basin may be used as the drainage for grey water from the shower or washing machines. The residues from detergent, soap, and cloth fiber can end up in the sump pit. This creates odors in the area over time. Cleaning the sump pit and pump regularly will help prevent unwanted odors. 

Waste Build-up

A sump pump may get dirty with time as it usually deals with wastewater. Different forms of waste building up in the sump pit contribute to causing foul smells. Accumulation of dirt and debris can also cause blockages. 

How to Deodorize a Sump Pump

A bad smell coming from the sump pump usually warns of something wrong in the system. Since you are aware of the causes of a smelly sump pump, let’s find out how to remove the odor. Here are some practical ways in which you can deodorize sump pump to prevent bad odors from growing.

Keep the Pit Covered and Air Tight

This is the easiest way to prevent smells from coming out of your sump pit. You can use an airtight cover so that air from the sump pit doesn’t come outside. If you cannot find a suitable air-right cover, you can tighten the seal. But this may not be the best solution since the smell still remains inside the pit.

Clean and Disinfect With Bleach

First, clean the sump pump and the basin with warm water and bleach. Use diluted bleach and scrub the basin and the pump carefully. This kills harmful microorganisms such as certain bacteria. Clean the whole drainage system at least once a year to kill germs and bacteria that cause odors. 

Keep Water Covering the Drain

Sump pits usually have some standing water at the bottom. But if the amount of water covers the drain hole, it will force odors to stay in the pipe. When the sump pump runs, the suction caused bad smells to creep inside your house. You can prevent this by keeping the water in the drains clean. 

Clean With Vinegar

Vinegar is another product that can remove bad odors from your sump pump pit. Mix a good amount of vinegar with hot water in a bucket. Then use a sponge to scrub the entire pit and the exterior of the sump pump. Afterward, dry everything to prevent corrosion. You can even use some liquid dish soap as an extra cleaning power mix.

Clean the Drain Lines

Cleaning the drain lines is not as easy as cleaning the sump pump. So, most people will usually clean it once a year. The best way to clean the drain lines is to pass in hot water through a hose. Add some soap and a few drops of bleach as you turn on the hose. Keep the water on high for several minutes to remove any clogs in the drain.

Sump Pump Odor Tablets: Rid-X Septic Tank Treatment Enzymes

Adding sump pump cleaning tablets are an easy way to deodorize the basin. These dissolvable pouches are pre-measured and easy to use. They are safe to use in pipes and tanks to remove bad odor. The natural bacteria and advanced enzymes included in these tablets break down the waste including oils, proteins, and grease. The formula contains no harmful chemicals and is natural and completely safe for your pipes and septic system. You can use the liquid formula when applying to drains. 

Caution: This contains bacterial spores and enzymes. Avoid contact with eyes and breathe dust. Avoid contact with the product if you are known to have allergies to enzymes and respiratory diseases or disorders.

Frequently Asked Questions

Why Does My Sump Pump Smell Like Sewer?

The reason that your sump pump smells like sewer could be due to the sewer itself. If there is some sewer line leaking in the area, it could contaminate the groundwater. As this groundwater seeps into your basement, the sump pump will start removing it, thus causing your sump pump to smell bad. Another possibility is smelly clogging built up in the pipes that need to be cleaned immediately.

Why Does My Basement Drain Smell Like Rotten Eggs?

A rotten egg smell usually symbolizes the emission of sulfur dioxide. If your basement drain smells like rotten eggs, then it can be coming from the sewer. To eliminate this odor, clean the drain pipes and add a small layer of water to the drain. 

Can I Put a Chlorine Tablet in My Sump Pump?

Yes, you can drop a chlorine tablet in the basin every few months if you have excessive smells coming from the pump. This helps to get rid of any algae growth causing the bad odor. Chlorine also helps to neutralize any iron ore algae and prevent it from clogging your sump pump.

Is Sump Pump Water Toxic?

It’s better to keep your sump pit empty and always keep it covered well. Do not allow pets to drink sump pit water as it contains different bacteria and chemicals that contaminate the groundwater. Although it may look clean, it could contain heavy metals such as lead, cadmium, or nickel. So discharge the sump pump water at a safe distance from the house.

Where Do I Discharge My Sump Pump Water?

Always discharge the sump pump drainage away from your home, at least at a distance of 20 feet. Do not let it flow onto sidewalks, driveways, or paved surfaces. If you cannot direct it to a sewer or storm system, then find a suitable location on your land. You can also install dry wells or catch basins to discharge the water safely underground.


If you still cannot get rid of the bad sump pump smell, you can call a professional to identify the problem. They will eliminate the cause of the smell and fix all the issues in your sump pump. If your sump pump leaks continuously due to cracks and damages, you can either fix them or purchase a new sump pump from a reliable brand.

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