How To Get Rid Of Bad Smell Coming From Your Sump Pump

Sump pump units are a key fixture in many states across the US, especially in Virginia. When rain falls, there’s a high chance it can gather up into the lowest areas of your town or city. 

Typically, these points are the basements of homes and businesses where the water can cause costly structural damage. To avoid that from happening, many home and business owners choose to install a sump pump.

There are times when you may notice a smell from sump pump units, whether that comes out as sewage or something else. These smells can be quite an inconvenience, especially if they waft up and out of the basement and into the rest of the building. 

Fortunately, they’re also a good way to catch any problems before they worsen.

We’ve listed a few of the most common sump pump smells you might get as well as how you can get rid of them. If you want professional help to get rid of the smell or if you suspect the smell is the start of a much larger problem, you can contact our team at Clover Contracting.

What Do Sump Pumps Do?

Though somewhat uncommon in a few states, sump pump units are a key fixture in many others that see a lot of rainfall or flooding. They often require far more excavation during installation, but in such states, sump pump units are vital in making sure their buildings stay dry.

Understanding how these systems work can often greatly help homeowners realize the answer to the question “why does my sump pump smell?”.

As the name suggests, sump pumps function by pumping out collected water from wherever it’s been installed to a special water disposal location, typically a dry well or storm drain. Sump pump units are usually installed in the basement of your home or business, so when the water enters the area, it fills the specialized basin to a certain point. If the water in the basin reaches the pump, the water gets removed.

There are additional parts to a sump pump, like the impeller fan, that create a low-pressure zone to keep the water moving continuously through the pipes. All the parts come together to keep the water from stagnating, especially since many sump pump issues start from said water. Getting a smell from sump pump units is just one of them. 

Common Problems That Can Make Your Sump Pump Smell Off-Putting

Quite a few of the sump pump smells are, in fact, signs that there’s something wrong with the system itself. However, it’s also important to remember that not all of these issues need immediate professional help. Many of the causes of the smells are incredibly simple and can easily be fixed by yourself. In many cases, you don’t even need much to fix it!

A Dried Out Sump Basin 

During the summer months, the temperature can rise high enough that excess dryness is a big issue. When it comes to dealing with a stinky sump pump, this dryness is a big deal. 

To reduce the smells that come out of the pump and its basin, a small amount of water needs to remain inside. The water inside acts as a sort of buffer that blocks any lingering gasses from escaping, much like the little section of pipe under your sinks.

However, when the temperature gets too high, that water barrier can evaporate. With nothing stopping the gasses from escaping, you may start noticing the off-putting smell.

Sewage Getting Into the Sump Pump Basin

Does your sump pump smell like sewage? If so, you’ll need to get the plumbing and ground around the pump checked. 

The smell of sewage is, naturally, a sign that a nearby sewer line broke or is leaking. Depending on its location and proximity to the sump pump, that wastewater can leach into the groundwater. Eventually, the sewage and its stench can travel back into the pump, especially if the two lines are connected.

A Collection of Stagnant Water 

While a dry sump pump basin is one cause for terrible smells, excess water can also be another. In this case, though, the smell is often the result of the pump failing to run or a poorly adjusted float switch. 

As mentioned, sump pumps have more parts than you might first expect, all to ensure that your basement and the rest of your home are damage-free. However, these parts, like with any other system, can be defective or fail. If your sump pump isn’t removing water from the basin properly, get a look at the check valve.

How to Fix a Bad Sump Pump Smell

There are a few different solutions you can try to fix a smell from sump pump units, though each depends on the cause. Simpler causes like stagnant water or a dry sump pump can easily be dealt with by altering the water in the basin. A dry sump pump basin simply needs water in it, so adding water to the basin is the best solution. Similarly, an excess of stagnant water can just be flushed out by adding enough water to activate the pump.

If neither of these options removes the bad smell after a few days, you can try mixing a chemical cleaning solution. Best used for sump pumps that are made out of cast iron or thermoplastic, bleach can get rid of that smell. All that’s needed is a cup of bleach diluted into a gallon of water. 

After giving it a quick mix, pour the solution into the basin until the water level rises enough to activate the pump’s system. Then you can start to clean the walls of the basin using a brush (or something similar). You can also use a bit of your diluted bleach solution if the basin or the brush is too dry.


As important as your sump pump is, terrible stenches can often make you wish you didn’t have one. Depending on the season, the smell can waft up through your vents and doors, making the rest of your home stink, too. Fortunately, both the causes and their fixes are simple, so trying them out is a great idea. 

If these smells persist, you can always contact our team at Clover Contracting.

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