Heavy rain is when sump pumps prove themselves, or fail. The failures we get called to almost always trace back to maintenance gaps that could have been caught in five minutes.
The most common failures
- Stuck float switch. Debris or a kinked tether prevents the float from rising. Pump runs dry or never runs at all.
- Frozen or blocked discharge line. Water has nowhere to go, the pump cycles continuously, the motor burns out.
- Power loss. Storms knock out power exactly when pumps are needed most. A battery backup is non-negotiable.
- Undersized pump. A 1/4 HP pump cannot keep up with a 100-year rain event. WNC homes typically need 1/3 to 1/2 HP.
- Old check valve. A failed check valve lets discharged water flow back into the basin, doubling pump cycles.
A 5-minute pre-storm checklist
- Pour a five-gallon bucket of water into the basin and confirm the pump kicks on.
- Verify discharge water exits at least 10 feet from the foundation, downhill.
- Check the battery backup — if it is more than 3 years old, replace it.
- Listen for a smooth motor sound (no grinding or rapid cycling).
- Confirm a working secondary pump or water-powered backup if the basement is below grade.
Sump pumps are insurance policies that have to be tested. They will not fail at a convenient time.