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Top Reasons Your Sump Pump May Smell


An off-putting sump pump smell causes concern. Indianapolis homeowners want to know the odor from their sump pump and sump pit is normal or if it points to larger sump pump problems. In most cases, the fix for a smelly sump pump can be done with ease. Other times, a professional plumbing services provider should be contacted to perform sump pump service.

That’s where Mr. Plumber comes in! Our licensed plumbers compiled all the information you need to know about how a sump pump works and why your sump pump smells. Because sump pumps collect water and deal with waste, homeowners want to make sure the sump pump smell isn’t out of the ordinary. With these tips, the differences are clear enough for everyone to see.

What Does a Sump Pump Do?

First and foremost, homeowners must understand what the sump pump’s function is in their home and why it’s so important for the sump pump and sump pump pit to remain odorless. In Indianapolis, sump pumps are particularly important because of the amount of rainfall our area receives and the resulting high levels of surrounding groundwater.

Here’s what your sump pump does for your home.

Sump pumps hold water in the pit and transfer it away from your home. The water moves from the pump to an area deemed safe for water disposal such as a storm drain or dry well away from the home. This prevents flooding in your basement from standing water.

In order to do this, the sump pump sits in a sump basin which lies at the lowest point in your basement. When pressure pushes surrounding groundwater into the foundation, the water migrates to the sump pit naturally because it resides at the lowest point. As water collects in the sump basin, a float switch will activate the sump pump once the water level reaches a designated level in the sump pit.

From there, the water leaves your home through drain lines with a one-way valve and into a safe area. Additionally, a fan-like device called an impeller forces water toward the sides of the pipe, which creates a low-pressure area. Because of this, the water continuously moves through the pipe. When it comes to water, the more it settles, the more it causes problems. When everything works as it should, your basement remains unflooded.

The sump pump smell can come into play when certain aspects of the system go without maintenance for long periods of time. Because of that, remember to keep maintenance at the top of your list the next time you call Mr. Plumber!

What a Sump Pump Smells Like

Sump pump odors mimic a variety of things when the system has an issue. The funky smell can stink up your basement, which leads to complete avoidance of the area. Here are some of the more common smells and foul odors you may experience with your sump pump.

  • Sewer gas. A gas-like smell can come from the sump pump. At first, the smell seems like gasoline, but it actually comes from the sewer. Sewage infiltration and a sewer line breach can cause sewage smells and raw sewage from sewer lines to seep into your home. Sewer gas passes into the house when the sump pump dries out, which leaks the smell into your home. This gas comes from the waste and contains nontoxic and toxic gases. In short, be aware of a gaseous smell!

  • Mold and mildew. Mildew is a common sump pump smell. Because the sump pump constantly has standing water inside, it grows mold and mildew. Like with anywhere that collects water, you want to make sure the sump pump stays as dry as possible without impeding the functionality of the unit to avoid these bad smells.

  • Maybe you smell rotten eggs—or more accurately sulfur—coming from your sump pump. Sump pumps are known to give off this foul odor for a few different reasons, but most commonly because of dirt build-up.

  • Waste. Here’s the obvious one—waste. Though it gets uncomfortable to think about, waste enters the sump pump on a daily basis. Because of that, waste materials build up over time. These build-ups occasionally lead to clogs that make sump pumps smell. In most cases, the sump pump only needs some cleaning maintenance with a bleach solution and a scrub brush to get rid of the smell.

Causes of Sump Pump Odors

The previous section dives into some of the different sump pump odors, but it’s important to know all the details. Sump pumps work day in and day out to keep your plumbing system clean, so make sure to know where to look if things go wrong. Here are some of the most common causes of a sump pump smells.

  • Dry sump pump. After long periods of use, sump pumps dry out. Over the dry season and dry periods, the sewer gas that collects in the basin gets released into the home because the water no longer shields the air from the gases. In the best case, this simply causes a foul odor or bad smell. However, in the worst-case scenario, sewer gas leaks cause health problems even in a small amount and are a fire hazard.

  • Stagnant water. Before they dry out, sump pumps collect fresh water. This water sits in the basin without much movement for extended periods of time. In this environment, mold and mildew flourish. This growth doesn’t change the functionality of your pump per se, but it gives off a musty, unpleasant smell from down in the sump pit.

  • Dirty sump pump. The cause of your sump pump smell might stem from how dirty it got over time. Because the sump pump deals with waste, it naturally accumulates dirt and other debris quickly. Though this doesn’t cause an initial issue, over time the build-up can lead to a blockage and pump smells.

  • Waste build-up. Waste build-up contributes to the sump pump smell. A sump pump gets used in a home often, which means it collects waste every single day. When you have a sump pump for a long period of time, that waste builds up. Of course, this causes a foul smell to permeate from the sump pit through your home.

  • Cracked or broken equipment. In the worst-case scenario, sump pump smells point to a cracked or broken part of your plumbing. This part could either be in your plumbing system itself or directly on the sump pump. Either way, this causes major issues for your sump pump.

How to Remove Sump Pump Smell

Now that you know the causes of sump pump smells, we can discuss some of the solutions to use when your equipment smells like sewage or other foul substances. Sump pump smells are often early warning signs of trouble somewhere in the system, so maintenance is necessary and you also may need to schedule service. Sump pumps require professional maintenance once a year, but there are things you can do at home to eliminate the foul odor it produces. Here are some of the best solutions to these common causes.

  • Seal cracks and leaks. One of the best ways to reduce the sump pump smells similar to mildew entails sealing the cracks and leaks. This goes for all of the plumbing in your home. Be sure to check all of your pipes and water systems for cracks or leaks and seal them with waterproof sealer. Additionally, check for cracks directly on the sump pump or in the concrete around the system. This gets rid of any excess water that leads to mildew or mold growth.

  • Clean the system. This fix for a sump pump smell seems simple, but to clean your sump pump you must be physically and mentally prepared. The task requires you to take out pump from the sump pit—remember to wear plenty of protection—and clean the pump with hot water. Homeowners should clean their sump pump every six months or once a year depending on how much stagnant water the environment collects over time.

  • Diluted bleach solution. Here’s another solution for the mildew smell. Use a diluted bleach solution to eliminate mold and mildew growth. All you have to do is pour a little bit of this solution into the sump basin. Even if mildew isn’t the cause of the smell, the bleach solution freshens up the system and helps reduce odors.

  • Refill the water. A sump pump smell caused by a dry basin has the easiest fix. Simply refill the basin with water and you notice a difference right away! Sewer gases are always present in the sump pump system, but with a layer of water, they are harder to smell. In a way, the water filters the gas particles, which takes away the smell as well as the negative side effects associated with sewer gas.

  • One of the best ways to prevent a sump pump smell is to take the time to perform preventative maintenance on your system. You can do this by regularly cleaning your sump pump, checking the overall health of your plumbing, and having a professional check your system every year. It’s the best way to keep odors at bay!

  • Call a professional. When you just can’t get rid of the sump pump smell, it’s time to call a professional to assess the issue. Mr. Plumber’s expert plumbers are ready to help you with all of your sump pump problems. We will remove the smell for you and fix any problems we find along the way.

Contact Us About Sump Pump Odors

Mr. Plumber in Indianapolis, Indiana wants homeowners to feel comfortable in their homes. That means living in a smell-free space with a sump pump that works like it should! A sump pump smell doesn’t need to get in the way of your comfort, so use these tips to eliminate the smell as soon as possible.

For more information on our plumbing services, feel free to contact us or check out our website. We offer Indianapolis homeowners advice on a variety of plumbing issues. Sometimes you can make do without a plumber, but when you’re in need, Mr. Plumber has your back! Call today to schedule a maintenance check. We’re excited to hear from you!

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