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Sump Pump Smell: Causes and Solutions

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You might smell something unpleasant coming from your sump pump if you have one in your basement or crawl space. It’s critical to locate and address the problem as soon as you notice a bad odor coming from your sump pump.

The common causes of sump pump odor are covered in this article from basement Savvy, including sewage backup, bacteria growth, debris buildup, dry traps, dead animals, and chemicals. Additionally, it offers thorough instructions for removing the foul smell, including cleaning the sump pit, checking for sewage backup, adding a sump pump pit deodorizer, installing a sump pit cover, using activated charcoal, checking ventilation, maintaining proper water levels, installing a UV-C light, and inspecting the drainage system.

What is a sump pump and why do I need one?

A sump pump is a tool that removes extra water from a basement or crawl space to help prevent water damage. It is typically installed in a sump pit or basin that collects water from drains or naturally occurring groundwater infiltration into the area. The sump pump then pumps the water out of the pit and away from the foundation of your home.

Causes of Sump Pump Smell

There are several reasons why your sump pump may produce an unpleasant odor. Some of the most common causes include:

Sewage Backup

A sewage backup in the main sewer line is a frequent reason for sump pump odor. Sewage may flow back into the sump pit when the sewer line is blocked or damaged, giving off an unpleasant odor. Additionally, it might make your toilets and drains gurgle.

Bacteria Growth

A musty or mildew-like odor may result from bacteria growing in standing water in the sump pit. This smell may be comparable to that of damp clothing or towels that have spent too much time in the washer. If the bacteria are not treated, they may also result in health issues.

Debris Buildup

In the sump pit, debris such as leaves, dirt, and other organic matter can build up and decompose, producing an unpleasant odor. This debris may also clog the pump and impair its performance.

Dry Trap

Sewer gases may escape from the sump pump’s trap if it is dry, giving off a rotten egg-like odor. A small amount of water will be retained in the trap to prevent gases from entering the living area.

Dead Animals

An unpleasant odor might be created if a mouse or rat falls into the sump pit and dies there. This may occur if the sump pump cover has gaps that allow animals to enter.


It may emit a chemical odor if you keep chemicals close to the sump pump, like in a nearby storage room. If the chemicals are toxic, this can be risky and needs to be addressed right away.

To effectively get rid of the sump pump smell, you must first understand what is causing it. To avoid further issues and ensure the security of your home and family, it is best to act right away.

Solutions to Get Rid of Sump Pump Smell

Now that you know the different reasons why your sump pump may produce an unpleasant odor, let’s discuss some solutions to get rid of the smell.

Clean the Sump Pit

Cleaning the sump pit is the first step to eliminate sump pump smell. Here’s how to do it:

  • Turn off the sump pump and unplug it.
  • Wear gloves and a mask to protect yourself from mold spores.
  • Remove any debris, sludge, or standing water from the sump pit.
  • Scrub the walls of the sump pit with a stiff-bristled brush and a mild detergent or bleach solution. Use one cup of bleach for every gallon of water.
  • Rinse the sump pit thoroughly with clean water.
  • Let the sump pit dry completely before turning the sump pump back on.

Check for Sewage Backup

If you notice a sewage-like smell coming from your sump pump, it’s crucial to check for a backup in your main sewer line. Here’s what you should do:

  • Contact a professional plumber to diagnose and fix the problem.
  • Ensure that the plumbing system is properly vented to prevent future backups.

Add a Sump Pump Pit Deodorizer

Sump pump deodorizers or Sump pit deodorizer are designed to eliminate odor by breaking down bacteria and other odor-causing agents. Here’s how to use them:

  • Purchase a sump pump deodorizer from a hardware store or online.
  • Follow the instructions on the package to add the deodorizer directly to the sump pit.
  • Allow the deodorizer to work for several hours or overnight before turning the sump pump back on.

Install a Sump Pit Cover

A sump pit cover can prevent debris from entering the pit and causing an odor. Here’s how to install one:

  • Purchase a sump pit cover from a hardware store or online.
  • Follow the instructions on the package to install the cover over the sump pit.
  • Ensure that the cover is properly sealed to prevent odors from escaping.

Use Activated Charcoal

Activated charcoal is a natural odor absorber and can be used to eliminate sump pump smell. Here’s how to use it:

  • Purchase a few bags of activated charcoal from a pet store or online.
  • Place the bags of activated charcoal directly in the sump pit.
  • Leave the bags in the sump pit for several days to allow the charcoal to absorb the odor.
  • Remove the bags from the sump pit and dispose of them properly.

Check the Ventilation

Poor ventilation can lead to moisture buildup and mold growth in the sump pit, causing a musty smell. Here’s how to improve ventilation:

  • Ensure that the area around the sump pump is properly ventilated by opening windows or installing a fan.
  • Use a dehumidifier to remove excess moisture from the air.

Maintain Proper Water Levels

Maintaining the proper water level in the sump pit can prevent the growth of bacteria and mold. Here’s how to do it:

  • Ensure that the sump pump is properly installed and functioning correctly.
  • Adjust the float switch to maintain the proper water level in the sump pit.
  • Regularly check the water level in the sump pit and adjust as needed.

Install a UV-C Light

UV-C lights emit ultraviolet radiation that is harmful to microorganisms and can kill bacteria and mold in the sump pit. Here’s how to install one:

  • Purchase a UV-C light from a hardware store or online.
  • Follow the instructions on the package to install the light in the sump pit.
  • Ensure that the light is properly positioned to expose the entire sump pit to UV radiation.
  • Turn on the UV-C light and allow it to run for several hours to kill bacteria and mold

How to Get Rid of Bad Smell from Sump Pump

Mold growth can be detected by a musty, sewage-like bad smell coming from your sump pump. Since mold prefers moist environments to grow in, a sump pump pit is the ideal place for it to do so. To stop mold from spreading throughout your basement, you must act quickly if you smell rotten eggs coming from your sump pump. To get rid of the musty smell coming from your sump pump, follow these steps:

  1. Turn off the sump pump and unplug it.

Before you start cleaning the sump pump pit, turn off the sump pump and unplug it from the electrical outlet. This will ensure your safety while you clean the pit.

  1. Put on gloves and a mask to protect yourself from mold spores.

Mold spores can cause respiratory problems, so it’s important to protect yourself with gloves and a mask while cleaning the sump pump pit.

  1. Remove any debris or sludge from the sump pump pit.

Using a small bucket or a scoop, remove any debris or sludge that may have accumulated in the sump pump pit. Be careful not to damage the sump pump or any of its components while you’re removing the debris.

  1. Clean the sump pump pit with a mixture of water and bleach.

Mix one cup of bleach with one gallon of water to create a cleaning solution. Pour the bleach solution into the sump pump pit, making sure to cover all the surfaces. Use a stiff-bristled brush to scrub the walls and bottom of the pit.

  1. Rinse the sump pump pit thoroughly with clean water.

After scrubbing the sump pump pit, rinse it thoroughly with clean water. This will ensure that all the bleach and mold spores are removed from the pit.

  1. Let the sump pump pit dry completely before turning the sump pump back on.

Once you’ve rinsed the sump pump pit, let it dry completely before turning the sump pump back on. This will prevent any electrical components from getting wet and potentially causing damage.

How to Make Sump Pump Smell Better

If you’re experiencing unpleasant odors emanating from your sump pump, you’re not alone. Many homeowners face the same issue, and it can be quite bothersome. Fortunately, there are several ways to make your sump pump smell better.

  1. Use a Sump Pit deodorizer Using a deodorizer is one of the simplest ways to get rid of sump pump odors. Deodorizers made specifically for sump pumps are widely available in hardware stores and online. They are available in a number of forms, including sump pump deodorizer tablets, powders, and gel packs. Simply drop them into the sump pump pit to release their fresh scent, which will cover up any offensive odors.
  2. Install a sump pump cover Additionally, installing a sump pump cover can aid in minimizing bad odors. A cover will stop odors from rising from the pit and filling your basement. To fit various sump pump models, covers come in a variety of sizes and materials, including plastic and metal.
  3. Keep the sump pump pit clean Regularly cleaning the sump pump pit is essential to prevent odors from developing. Remove any debris, dirt, or sediment that has accumulated in the pit. If the pit is clogged, it can cause the water to stagnate and create a foul odor. You can use a hose to flush out the pit and remove any remaining debris.
  4. Consider a sump pump with a built-in deodorizer If you’re in the market for a new sump pump, consider purchasing one with a built-in deodorizer. Some sump pumps come equipped with this feature, which helps keep the air fresh and free of unpleasant odors. This option may be a bit pricier than a standard sump pump, but it could be worth it in the long run.
  5. Check for leaks Another reason your sump pump may be producing a bad smell is due to leaks in the discharge pipe or the sump pump itself. Leaks can cause stagnant water to accumulate and create a foul odor. Check for leaks and repair them promptly to prevent further damage.

Checkout Our Guide to : 10 Smart Ways to Cover Your Sump Pump


Many homes require a sump pump, but if it starts to smell, it can also become a problem. There are numerous causes of odor development in sump pumps as well as numerous solutions to the problem. You can maintain the cleanliness and fresh scent of your sump pump by using the advice provided in this article. Don’t forget to regularly check and maintain your sump pump to avoid any issues from arising.

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