What To Do When Sump Pump Overflows

An overflowing sump pump can be a nightmare for a homeowner. Your sump pump is your line of defense against flooding, and we don’t have to tell you the financial nightmare that can come from a flooded basement. In this article, we’re examining why your sump pump might be overflowing and how you can solve this problem before it becomes a massive issue.

old sump pump in a basement

Unfortunately, your sump pump could be overflowing for many different reasons!

Common reasons include a clog in the sump pump line, a loss of power to the pump, abnormally high water levels, a problem with the check valve, an inadequate sump pit, and more. The key to fixing the problem is to identify the issue. In our guide, we get into detail, letting you know what to look for and how to approach each situation.

How Does a Sump Pump Work?

To properly understand why your sump pump is overflowing, it’s best to start by knowing how your sump pump works.

A sump pump goes into the lowest point of your home to prevent it from flooding from beneath. A sump pump goes into a sump pit, which is dug beneath your home. Water flows into the sump pit, both from the drains in your home and exterior sources (rainfall, water table, etc.). The sump pump collects this water and pumps it up and out of your house to a safe distance where the water won’t be an issue.

Why Is My Sump Pump Overflowing?

Unfortunately, so many different variables can cause water backup and basement flooding, so it is impossible to give you a one-size-fits-all solution to your sump pump problem. For this reason, we’ll cover the most common reasons your sump pump might be overflowing and how to rectify each issue. The first step in solving the problem is identifying the issue.

Too Much Water (Pump not Powerful Enough): It might be the case that your pump can’t keep up with the amount of water flowing into the sump pit. As a result, flooding can occur.

This issue is generally because your sump pump is inadequate to handle the water level or precipitation typical to your area. If your area typically receives a lot of excess water in the form of precipitation or if the water table is high, then you may need a very powerful sump pump to rid your home of this water. If your sump pump isn’t up to the task, then you could see it overflow, especially during periods of heavy rainfall.

The solution to this problem often requires a new, more powerful sump pump. If your sump pump can’t keep up with your area’s average groundwater levels, then a new unit is required.

Clog in the Lines: Your sump pump pumps water out of your home through a line (pipe). The sump pump takes the water in the sump pit, pumps it upward, and then out of your home to a safe distance. If any of these lines gets clogged, the whole system can back up and cause flooding in the sump pit and eventually into your home.

Unfortunately, clogs can be commonplace, especially if your sump pump installation was inadequate. You’ll likely want a professional to inspect your lines for any leaks and clear them as necessary.

Loss of Power: If your house loses power, then your sump pump may stop working, which is especially concerning because your power may go out in a thunderstorm when you need the sump pump most!

Usually, this issue will resolve itself quickly enough to not be an issue, except in severe rainstorms. Some homeowners opt to install a backup battery on the sump pump that can kick in when it’s needed.

Check Valve Problem: Your sump pump utilizes a check valve to ensure that water doesn’t flow back into the sump pit after it’s pumped out. Your sump pump has to pump water directly upward so that to pump it outside of your house. If this valve becomes clogged or malfunctions, then you might experience flooding in your sump pit.

If you think this is the issue, you need to have a professional inspect your system and fix the valve.

Sump Pit is Too High/Small: It might also be the case that the size of your sump pit is inadequate. If your sump pit is too small, then it may fill up too fast and may require the sump pump to work overtime to clear the pit. If the pump falls behind, then flooding can occur! This can also be the case if the sump pit wasn’t installed deep enough, and the water table frequently brings water above this level.

If this is the case, you’ll likely need to hire a professional to expand your sump pit.

Stuck Switches: Your sump pump has a float switch that activates the pump when the water reaches a certain level. If this switch is faulty, then the pump won’t turn on, and it won’t clear the pit, which might be the case when the switch becomes clogged with debris, or it might be the case that your machine is old and broken.

In either instance, you need to inspect the pump (or hire someone to do it) and see whether you can fix the clog or whether the pump needs to be replaced.


Thanks for reading our guide to an overflowing sump pump. As you can see, the root of a sump overflow problem can be quite complicated. The common link piecing together every solution is that you must inspect the sump pump to identify the problem. If you’re no expert in this field, then you’ll want to hire an expert to do this for you. An expert can identify the problem and give you the proper fix.

Leave a Comment

Your email address will not be published.