Sump Pump Running Constantly? 3 Easy Fixes to Save Your Basement

 During a seasonal home inspection in Naperville, Illinois, a homeowner led me down to his basement. Before we even reached the utility closet, I could hear a faint, continuous hum. "It’s been doing that for three days straight," he said, pointing to his trusty Zoeller M53 sump pump. "It just won't shut off."

A sump pump that runs constantly is a ticking time bomb for your electricity bill and the pump’s motor. Whether you rely on a heavy-duty Zoeller, a Liberty Pump, or a Wayne system, these machines are designed to cycle on and off only when water levels rise.

If your pump is running non-stop even when there hasn't been a heavy rainstorm, you need to act fast before the motor burns out and leaves your basement vulnerable to flooding. Fortunately, you can usually diagnose and fix this issue yourself without calling an expensive plumber. Here are the 3 most common reasons your sump pump won't stop running and how to fix them.

1. The Stuck Float Switch (The Most Common Culprit)

The float switch is the component that tells your pump when to turn on and off. As water fills the pit, the float rises like a buoy. Once it reaches a certain height, it triggers the switch.

 The Master Detail: Over time, as the pump vibrates during operation, it can physically shift inside the plastic basin. When this happens, the mechanical float arm can get wedged tightly against the rough corrugated wall of the sump pit. Because the float is trapped in the "up" position, the pump thinks the pit is constantly full of water and never shuts off.

 How to fix it: Disconnect the power first. Reach into the pit and gently nudge the pump back into the center of the basin. Ensure the float has at least a few inches of clearance all around it to move freely up and down.

2. A Failed or Blocked Check Valve

The check valve is the small plastic or rubber valve installed on the discharge pipe just above your sump pit. Its sole job is to let water flow out of your house but prevent it from rushing back in once the pump turns off.

 

The Technical Reality: If a small piece of gravel or debris gets trapped inside the check valve, it won't seal properly. When the pump stops, all the water inside the vertical discharge pipe will rush straight back down into the pit. This triggers the float switch again, causing an endless, exhausting loop of pumping the exact same water over and over.

 How to fix it: Inspect the valve for cracks. If you hear a loud, repeating thumping sound every time the pump attempts to shut off, the check valve internal flap is likely broken and needs a quick, cheap replacement.

3. The Pit is Too Small or the Water Table is High

If you live in an area with a naturally high water table, or if your basement basin was improperly sized during construction, your pump simply might be struggling to keep up with the continuous underground influx.

 The Pro Move: If the float is moving freely and the check valve is working, check the switch setting. You may need to adjust the tether length of your float switch so that it requires a higher water level to trigger the motor. This gives the pump a well-deserved rest between cycles.

Summary

A constantly running sump pump is usually a cry for a simple mechanical adjustment. By centering the pump in the pit, cleaning the float, and verifying your check valve, you can prevent a catastrophic motor burnout. Check your pit at least twice a year to keep your basement dry and your mind at ease!