Why Does My Sump Pump Smell? (How To Get Rid Of Them)

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The primary reason behind using a sump pump is to protect your basement and the foundation of your home from any sort of water damage. Excess rainwater stored in the soil gets collected into the sump pit, which is then removed by the sump pump. Now, if you have been using a sump pump for years then, you know that there are a few problems that can arise if the pump isn’t properly taken care of. Among them, foul odor coming out of your sump pump is one of the major issues.

There can be a number of reasons that can result in such putrid smells, for example

  • stagnated water
  • dryness
  • mechanical problems of the pump
  • waste build-up
  • drainage issues

Also, with each related issue, your pump can give off a distinctive smell. With this, you can identify the problem associated with your pump and then fix it.

Why Does My Sump Pump Smell

Reasons of Smelling & How To Get Rid of Sump Pump Smell

· Stagnated Water (A Foul Odor)

As you may know, your sump pump only activates after the water level inside the pit reaches a certain level. For this, the float switch sends a signal to the pump which starts pumping out the accumulated water. However, if the water at the bottom of the pit does not get pumped out, it will cause water to go stale, and then eventually, it starts to give off an awful odor. Also, the prolonged dampness of the pit wall becomes a perfect breeding ground for mold and harmful bacteria.

To tackle this, you need to manually remove the debris and dirt from the bottom of the pit and then scrape off the mold from the walls. Later, you can add bleach to get rid of the smell.

· Dryness (why does my sump pump smell like rotten eggs)

Sometimes, you may find the smell of rotten eggs coming from your sump pit. This usually happens during the dry season, when the water in the pit dries out, and a significant amount of dirt builds up. The sulfur dioxide gas escapes from the sewers and exits out through the pit. It is known to give off a foul smell of rotten eggs. To prevent the gas from escaping into your home, pour fresh water into the sump pit. This will block the drain lines and the outgoing pipes from where the gas emerges. Also, regularly maintaining the drain pipes prevents the gas from building up.

Mechanical problems can happen if you live in an area that is prone to a lot of precipitation. Your sump may start to smell while pumping. It is quite obvious that your sump pump is at full throttle after a heavy storm. So, if your sump pump begins to stink, then your pump is over-draining the pit and is consuming a large amount of power. To resolve this, make sure you get a pump of the right size.

· Waste Build-Up (Smells Like Gas/ Smells When it Rains)

It can be rather unpleasant when there is a gas-like stench coming out of the pump area of your basement. It may sometimes seem like a gasoline leak; however, the smell may actually come from waste that has accumulated over time. This can happen either during the dry season or after heavy rainfall. The gas can be of toxic or non-toxic nature. However, if the gas happens to be toxic, then it can be a matter of health issue or be a fire hazard.

Keeping a layer of fresh standing water in the sump pit can remove the smell. And, discarding the waste material can also considerably reduce the smell.

· Drainage Issues (Smells Like Poop/ Dead Animal/ Skunk/ Sewer)

As we mentioned earlier, your sump pump is designed to collect excess groundwater from the vicinity of your house. So, if there is a crack or a break in your sewer system then, the water from your tubs, sinks, toilets, and even laundry will leak into the soil. This will eventually end up in your sump pit and cause not only your pump but also your house to smell like a sewer.

One of the ways to figure out if there is an actual leak in your plumbing, what you can do is- add a sufficient amount of dye to the toilet water and then flush it. If there is a leak, then the color-dyed water will show up in your sump basin. Another way to understand if there is a leak is to fill your bathtub with water up to the brim and then drain the tub completely. If your sump pit suddenly fills up then, there is definitely a breach in the pipes.

You can also get the help of professional plumbing services. The plumber can pinpoint the location of the rupture by inserting a cable with a camera at its tip to inspect the sewer lines.

Cleaning Sump Pump with Vinegar

It may come as a surprise to many of you but, vinegar is, in fact, a great solvent for getting rid of the awful odor. Whether it is the smell of rotten eggs or that of poop, it removes the smell easily.

For this, all you have to do is, add a large amount of vinegar and a little bit of dish soap into a bucket full of hot water. Also, you will need a sponge for scrubbing. You can begin by cleaning the entire sump pit and then continue to scrub the exterior of your pump. Don’t forget to dry off your pump after you are done cleaning. Doing this will reduce the chances of oxidation taking place.


As you can see, your sump pump is useful to you only when you take care of it on a regular basis. If you hesitate and slack off, you will end up in a messier and smellier situation, such as waste build-up, growth of mold and mildew, and gut-wrenching odor. Although in some cases, the foul smell may not be such a bad thing. It can, in fact, act more like a warning sign especially, in the case of a busted sewer line.

Hopefully, with the distinctive and peculiar smell emitting from your basin, you are able to identify the type of problem with your sump pump. We hope this was useful to you. Thank you!

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