Emergencies
Sump pump not working? Causes and fixes
Updated
Short answer
Check power first, then the float: if it's stuck against the pit wall the pump won't start. A pump that runs but doesn't empty the pit often has a frozen or clogged discharge line or a stuck check valve. If the pit is about to overflow, call right away.
Pump won't run
- GFCI outlet tripped or unplugged
- Float stuck on the pit wall or a cord
- Failed switch or motor
Pump runs but water doesn't drop
- Discharge line frozen outside (common in Colorado winters)
- Check valve installed backward or stuck
- Clogged intake screen
Pump cycles constantly
A failed check valve lets water fall back into the pit, so the pump keeps restarting. A high water table in spring can also keep it busy. Constant cycling burns out motors, so have it looked at.
What the plumber does
The plumber tests the float and switch, checks the check valve direction and condition, clears the intake screen, and confirms the discharge line drains away from the foundation.
If the pump is old or undersized for the inflow, they'll recommend a replacement, often with a battery backup and a high-water alarm for finished basements.
- Float, switch and motor tests
- Check valve and discharge line
- Replacement and backup options
When to call a plumber
Call if the problem keeps coming back, if water is reaching walls, ceilings or electrical areas, or if any step above involves gas, a torch or opening a sewer line. A licensed plumber handles sump pump service and will explain the cause before starting.
Questions
How do I keep my sump discharge from freezing?
Can a sump pump connect to the sewer?
This guide is general information for Colorado homeowners, not a substitute for an on-site diagnosis. Local codes vary; your plumber and building department have the final word.