A sump pump that runs but does not remove water usually has a clogged intake screen, a blocked or frozen discharge line, a check valve that is stuck or installed backward, or a broken impeller. In each case, the motor is working, but water is not getting out of the pit.
A Clogged Intake
The pump pulls water through a screen near its base. Gravel, silt, and debris from the pit can block it. When that happens, the pump runs but moves little or no water. Unplug the pump before checking the intake, and clear any debris you can see.
Discharge Line Problems
The discharge pipe carries water out of the house. If it is crushed, clogged, or frozen in winter, the water has nowhere to go. Check the outside end of the pipe for ice, leaves, or dirt. A line that runs a long distance or uphill can also put strain on a smaller pump.
Check Valve Issues
A check valve on the discharge pipe keeps pumped water from flowing back into the pit. If it is stuck closed, the pump cannot push water out. If it was installed facing the wrong direction, the same thing happens. You may notice the pump straining with a louder sound than usual.
A Worn or Broken Impeller
The impeller is the spinning part that moves water. If it cracks or comes loose from the motor shaft, the pump hums and runs but water stays put. This usually means a repair or a new pump.
Running dry for long periods can burn out the motor. Unplug it if it keeps running with no result, and have the intake, valve, and discharge checked. A pump check is also a good time to look at nearby drains and pipes for wear. Call JPR Plumbing at (833) 603-1840.