Why Is My Sump Pump Running Constantly? (Causes & Fixes)

Quick Answer

A sump pump running constantly is most commonly caused by a stuck or tangled float switch, a broken check valve allowing pumped water to fall back into the pit, a high local water table after heavy rains, an undersized pump, or a clogged discharge line. Disconnect power before inspecting the float.

Is It Normal for a Sump Pump to Run Continuously?

During extreme rain events, frequent cycling is normal. However, a pump should never run 24 hours without shutting off. Continuous operation causes motor overheating, electrical breaker trips, and premature unit failure.

5 Common Reasons a Sump Pump Won't Turn Off

Inspect these common mechanical issues:

• 1. Stuck Float Switch: Debris or pump vibration can wedge the float against the basin wall in the "on" position.
• 2. Broken Check Valve: Allows evacuated water in the discharge pipe to rush back into the basin, triggering an endless restart cycle.
• 3. Clogged Discharge Pipe: Exterior blockages from ice, dirt, or debris prevent adequate water evacuation.
• 4. Undersized Pump: A 1/3 HP unit struggling in high-inflow environments where 1/2 HP or 3/4 HP is required.
• 5. High Ground Water Table: Persistent water table saturation keeping the basin filled for days after a storm.

Safe DIY Troubleshooting Steps

1. Unplug the pump from the GFCI outlet before touching the basin.
2. Check the float arm to ensure it moves freely without scraping the basin wall.
3. Remove gravel, silt, or debris from the pit bottom.
4. Inspect the exterior discharge pipe to ensure water flows away freely.
5. Plug back in and test by pouring a bucket of clean water into the basin.

Frequently asked questions