Sump Pump Running but Not Pumping Water

Last Updated on by Anthony Brown

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    Notice that your basement sump pump is running but not pumping water? This is a sure fire sign of a mechanical or drainage problem that needs to be fixed ASAP.

    In this article we will explore the 5 most common reasons why a sump pump will run without draining water and how to fix the problem.

    Zoeller M53

    In most cases these problem can be fixed with a little elbow grease but if you need a new pump we recommend the Zoeller M53.

    How to Tell The Pump is Not Pumping

    The first step is to check if your pump is pumping water. This can be done by filling up the basin with a few gallons of water – high enough so the water level raises the float and activates the motor. Once the float switch activates the motor check the end of the discharge pipe to see if water is coming out. If the water level is not dropping in the pit but you can hear the motor the pump is not properly draining.

    Having Trouble Telling If The Water Level is Dropping?

    Try sticking a ruler vertically into the bottom of the pit so you can see exactly how many inches of water are in the pit. This will give a good idea if the pump is draining any water.

    5 Reasons Why Your Pump is Not Draining Water

    1 – Clogged Drain Lines

    Clogged drain lines are one of the most common causes of a pump not pumping water. When water can’t exit out the end of the NPT lines water will eventually flll up the lines, body and basin.

    You can prevent clogs from happening by keeping leaves out of the lines and conducting normal scheduled maintenance both the pump and rain lines.

    2 – Broken Impeller

    The impeller is responsible for push water from the interior of the pump down the drain lies. Unfortunately this part is highly sensitive and can be damaged by small pebbles or other debris.

    If the impeller can’t spin or has been cracked or chipped there is a good chance you will need a new pump. The best way to protect the impeller is with a screen to prevent particles from entering the interior of the pump.

    You can tell if the impeller in working by feeling the body of the pump while it is running – you should be able to feel the inside spinning!

    3 – Burned Out Motor

    Burned out motors are usually cause by overworked pumps. Make sure the properly estimate how much water will be entering your pit. Too much water and too small of a pump will cause a burn out and flood – and on the other hand – too powerful of a motor with no water to drain can also cause problems.

    Most houses will do best with a 1/2 horsepower pump like the Zoeller M53 Mighty Mate.

    4 – Broken Check Valve

    Another potential problem spot is the check valve. The check valve is responsible for forcing water. The check valve is responsible for preventing water from flowing back into the pool after exiting, in some cases if it can become damaged or stuck and prevent water from entering the drain pipe.

    Need A New Check Valve?

    Finding the right model can be tough – read our full check valve guide.

    5 – Electrical or Mechanical Problems

    Like any appliance sump pumps can have electrical and mechanical problems. These issues can mostly be avoided by buying a high quality pump that is the right size for your basin and performing maintenance on your system.