How to Fix a Sump Pump That's Not Working
A sump pump failure during heavy rain can lead to a flooded basement in hours. Most sump pump problems are simple: stuck floats, clogged intakes, or tripped breakers. Diagnosing the issue quickly can save thousands in flood damage.
Likely Causes
- 1Float switch stuck or tangled on the pump or pit wall
- 2Clogged discharge line (frozen in winter or blocked by debris)
- 3Tripped GFCI outlet or circuit breaker
- 4Failed motor — pump has reached end of life (7–10 years typical)
- 5Pump is too small for the volume of water entering the pit
A failed sump pump during heavy rain can cause significant basement flooding within hours. Test the pump before storm season.
How to Fix It: Step by Step
- 1Check the power supply
Make sure the pump is plugged in. Check for a tripped GFCI outlet (press the reset button) and look for a tripped breaker in the panel. Sump pumps should be on a dedicated circuit.
- 2Manually test the float
Lift the float by hand or pour water into the pit until the float rises. The pump should activate. If it doesn't, the float switch or motor has failed.
- 3Check for a clogged discharge line
The discharge pipe moves water away from the house. Check for blockages at the outdoor exit point. In winter, the pipe may be frozen — pour warm water into it or use a hair dryer.
- 4Clean the pump screen
Disconnect the pump and remove it from the pit. Clean the inlet screen at the base of the pump using a stiff brush and water. Debris is a common cause of reduced flow.
- 5Replace the float switch
If the motor runs when plugged in but the float won't activate it, replace the float switch. Float switches cost $15–$40 and are easy to swap on most pump models.
- 6Replace the pump if motor has failed
If the pump hums but doesn't move water, or makes no sound at all, the motor has likely failed. Match the new pump's horsepower (1/3 HP or 1/2 HP) to your pit size and water volume.
Materials & Tools Needed
Warning Signs It's Getting Worse
- ⚠Pump runs every few minutes even during dry weather (high water table or crack in foundation)
- ⚠Grinding or rattling sounds when the pump runs
- ⚠Rust or corrosion on the pump housing
- ⚠Basement smells musty even without visible water
When to Call a Professional
Call a plumber if the pit is filling faster than any pump can handle (possible groundwater intrusion), if the discharge line needs rerouting, or if you want a battery backup system installed with an alarm.
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