10 Most Common Reasons for Sump Pump Failure

A sump pump is a crucial part of your home’s flood protection system. It is responsible for collecting and removing water accumulated in the sump basin and typically runs automatically.

However, failure to properly maintain your sump pump can lead to costly repairs or replacements. It can also cost you a few thousand from water damage to your home. When you have a sump pump failure you could end up with a flooded basement or worse, and may need to rely on flood insurance to cover the cost of the water damage that can occur.

You would be surprised to know most sump pump failures are due to easily avoidable causes, and if you are well aware, you can easily avoid them. Most frequently sump pump failures can occur due to clogged discharge lines or a frozen discharge pipe, but your pump can also fail if you do not maintain your sump pump regularly. Anytime a pump cannot drain water from a sump pit you are likely to expect some flooded basements.

This blog post will explore the top 10 most common reasons for sump pump failures you should look out for to keep water flowing out of your house and prevent standing water from collecting in the bottom of your home.


10 Top Reasons for Sump Pump Failure

Here are the 10 most common reasons for sump pump failure:

1. Improperly Sized Unit:

One of the most common mistakes when selecting from all the sump pumps available is choosing a unit that is too small or too big for the application. An undersized unit will have to work overtime and will inevitably fail prematurely because it is an overworked pump. Conversely, an oversized unit will run less frequently, leading to an increased likelihood of corrosion and mechanical problems. If you need help selecting a properly sized unit you can consult with a trained professional or find out what size pump your neighbors are using.

2. Worn or Damaged Float Switch:

The float switch is responsible for activating the sump pump when water levels rise and deactivating it when they return to normal. A worn or damaged switch is one of the most common reasons for sump pump failure followed by a stuck switch. Checking if you have a failed or stuck switch is easy because most pumps will let you bypass the switch and plug the pump directly into the wall. If the pump still works when plugged into the wall but never turns on when going through the switch it’s pretty clear the switch is the reason your sump pump fails to pump water out. Replacing a float switch is a fairly simple and inexpensive repair that can be done by yourself or by a trained professional.

3. Debris in Sump Basin:

If there is too much debris in the sump basin, it can prevent the float switch from operating properly or block the discharge pipe, causing the sump pump to run continuously. It is easy to tell if you have a clogged sump pump because you will actually be able to see that the water never leaves your pit even though the pump is working to try removing it. If you pull the pump out of your sump pit you can check if the pump impeller is being restricted which could be causing your clogged pump. Therefore, it is important to periodically clean out your sump basin to remove any accumulated debris.

4. Corroded or Worn Pump:

If your sump pump is more than five years old, it is likely beginning to corrode and wear out. Over time, the seals and bearings will deteriorate, leading to reduced performance and failure. Replacing an older sump pump with a new one can significantly extend its lifespan, just make sure you install it correctly or an improper installation could cause you more headaches than you wanted.

5. Improperly Installed or Maintained Discharge Pipe:

The discharge pipe (or discharge line) is responsible for carrying water away from the sump basin and should be properly installed and maintained to prevent leaks or blockages. If the discharge pipe becomes blocked, it can cause the sump pump to run continuously, leading to premature failure and usually resulting in a flooded basement. This is one of the most common sump pump problems and there are many different accessories you can use to make sure your plumbing stays clear and you don’t get a frozen discharge pipe. Inspect the discharge line regularly to ensure it is clean and in good condition and you can consider getting a pressure sensor to detect when excess water is not leaving your drain pipe.

6. Improperly Installed or Maintained Check Valve:

The check valve is responsible for preventing water from flowing back into the sump basin after being pumped out. If you have a broken check valve that, it can allow water to flow back into the sump basin, which would cause all sump pumps to run continuously in this situation. Fortunately most valve problems are easy to diagnose if they have failed (they will let water flow both ways when they have failed) and some nicer ones are even clear so you can see if the flapper is not shutting correctly. Inspect the valve regularly to ensure it is functioning properly.

7. Mechanical Damage:

If the sump pump is hit by a hard object or otherwise damaged, it can cause problems with the float switches, seals, bearings, or other components. As a result, the sump pump fails and may not operate properly or could even not respond to power altogether. If your sump pump is damaged, it is important to have it repaired or replaced as soon as possible. Fortunately with the help of our website finding a replacement sump pump should be easy!

8. Improper Installation:

If the sump pump is not installed properly, it can lead to several problems, including switch issues, faulty plumbing, or poor drainage. If your sump pump was recently installed it could be possible to correct it before long term damage occurs, but if you don’t catch it soon enough you could need a replacement sump pump all together if the bad installation ended up destroying your pump by overworking it. Don’t forget you may want to add a small air relief hole into your pipe so air pressure does not build up.

9. Power Failure:

If there is a power outage or the pump is not plugged in, it will not be able to operate. As a result, water will build up in the sump basin and could potentially cause flooding because your primary pump is not removing it from your sump pit. During power outages you will need to have some way to continue moving water out of your house. Make sure your sump pump has a backup power source in case of a power outage like a backup generator or something similar.

10. Inadequate Maintenance:

One of the most common reasons for sump pumps to fail is inadequate maintenance. It is important to regularly check the sump pump and basin for debris, clean the discharge pipe, inspect the float switches & check valve. By performing simple maintenance tasks, you can significantly extend the lifespan of your sump pump. The most significant maintenance task you can do is inspection and cleaning which can be done with a vinegar solution.

Expert Tips to Avoid Sump Pump Failure

The followings are some tips from our experts to help you avoid sump pump failure:

  • Please remember that selecting the right sized of pump for your needs is very important. Overworked pumps will usually fail prematurely and oversized sump pumps will have mechanical issues.
  • If you notice your sump pump running more frequently than it used to, or if it seems to be working harder than it should, this could be an early sign of trouble. Please give us a call so we can help you troubleshoot the problem and prevent future issues.
  • Regular maintenance is key to preventing sump pump failure, as with any mechanical device. Be sure to clean your sump pit regularly and inspect the float switch, check valve, and discharge pipe. By performing simple maintenance tasks, you can significantly extend the lifespan of your sump pump.
  • Always have a backup power source for your sump pump in case of a power outage. A battery backup system is a great option to ensure your pump will continue to operate even when the power is out. Some backup systems can even use the water pressure in your home instead of a battery in the event of a power outage.
  • Check to see if you have any air holes in your plumbing
  • If you do experience a problem with your sump pump or your sump pump pit, it is essential to have it repaired or replaced as soon as possible. Ignoring a problem will only worsen and could lead to flooding or other damage.

While sump pumps are typically very reliable, anything mechanical can fail. By following these tips and being proactive about maintenance, you can help prevent sump pump failure and ensure your basement stays dry even during power outages.

Frequently Asked Questions

What causes sump pump failure?

Many things can cause your pump to fail but with proper maintenance you can prevent problems with your drainage system. We recommend quarterly maintenance and inspection of your pump system, so just remember to check the pump every time you replace your furnace air filter and you will be able to keep your basement dry.

How to check sump pump for failure?

There are a number of ways a sump pump system can fail, as detailed above, but the best way to locate the failure is by isolating the different components to find the one that is causing the trouble. It’s very rare that more than one component will fail on your sump pump so try to test each part individually until you find the one causing the problem.

How to prevent sump pump failure?

Simple maintenance tasks you can perform on your sump pump can prevent premature sump pump failure and monitoring the system periodically for signs of trouble can keep your drainage system working flawlessly.

What do sump pumps do?

It is a system designed to remove water from the lowest point of your house from collecting which can cause structure and property damage. Usually a drain tile or some method of collecting water from the outside of your foundation will bring the water into your sump pit, and a float activator on your pump trigger the pump system to spin the motor shaft to move water out of your basin.

Final Words

Sump pump failure is a severe problem that can lead to flooding and other damage to your home. However, by understanding the common causes of sump pump failure and taking steps to prevent it, you can protect your home from this potential disaster.

We hope this article has been helpful. Please write them in the comment section if you have any further questions. We’re always happy to help!



Bill is a DIY plumber, handyman, and homeowner with more than a decade of experience. He has replaced and repaired sump pumps, backup pumps, float switches, check valves, and many other things around his family home. An engineer and tinkerer at heart, he is always looking to see how things work and taking on new home projects that help him grow his skillsets. He is a husband and father of two boys, has a bachelors degree in Computer Engineer and minor in Mathematics and likes to make homebrew beer in his free time.

      Sump Pump Advisor