The ten-minute test
- Lift the lid and look: debris, gravel or a loose liner?
- Ease a bucketful into the sump.
- Watch for the float to rise and the motor to hum.
- Make sure the level falls and the motor stops on its own.
- Listen for a thunk as the check valve closes; no water should fall back.
- Go outside and confirm water came out at the discharge.
What to clean
- Pump intake screen, often caked with silt
- Pit floor, removing stones that can jam the impeller
- Discharge outlet outside, cleared of leaves, snow and ice
The heaviest storms often take out hydro. A battery backup pump with its own float and check valve keeps working for a while.
From the counter
Warning signs
| Sign | Probable cause |
|---|---|
| Pump runs but water does not drop | Clogged intake, broken impeller, frozen discharge |
| Short-cycles every few seconds | Failed check valve or float set too tight |
| Hums, does not pump | Jammed impeller or failing motor |
| Never starts | Tripped GFCI, stuck float |
Winter discharge: if the outside line freezes, the pump runs against a blocked pipe. A freeze-relief fitting near the house gives water a way out.
Power cuts
The heaviest storms often take out hydro. A battery backup pump with its own float and check valve keeps working for a while. Test it too: unplug the main pump and pour water in. Replace the battery on the maker's schedule.
Time for a new pump?
A loud, sluggish or ancient pump, swap it before spring rather than during it. A spare pump on the shelf is a cheap form of insurance for a basement that takes a lot of groundwater.
Questions
How often should a sump pump run?
It depends on groundwater. Some run constantly in spring and rarely in summer. Sudden change in pattern is worth checking.
Can I discharge the sump into the floor drain?
No. Sump water must go outside, not into the sanitary sewer.