What Is a Sump Pump?
A sump pump is a pump installed in a pit at the lowest point of a basement or crawlspace that removes groundwater collecting there and discharges it away from the building. It runs automatically when a float switch detects rising water. Sump pumps are the primary defence against basement flooding in areas with a high water table or heavy seasonal rainfall.
The failure mode that matters
The scenario that floods basements is a heavy storm that also cuts power. A primary pump running on utility power has no answer to that, and it is the single most common way sump systems fail: not because the pump broke, but because the electricity stopped during exactly the event the pump exists for.
This is why a battery backup, or a water-powered secondary pump, matters more than the brand or capacity of the primary unit for any finished basement.
Other common failures
- Float switch stuck against the pit wall or tangled on the cord, the most common mechanical failure
- Discharge line frozen, blocked, or disconnected outside, so the pump runs and returns the same water
- Check valve failure, letting discharged water flow back into the pit
- Motor burnout from prolonged continuous running
- A pump undersized for the actual inflow, which works in a test and fails in a storm
Frequently asked questions
How do I test my sump pump?
Pour a bucket of water into the pit and watch. The float should rise, the pump should start, the water level should drop noticeably, and the pump should shut off. Do this a couple of times a year, and always before the wet season. It takes two minutes.
How long do sump pumps last?
Seven to ten years, less if it cycles frequently. Because they fail without warning and always during a storm, replacing at the end of expected life is genuinely cheaper than waiting to find out.
See also
Related services
- Emergency Sump Pump RepairRepair and replacement of failed sump pumps, including battery backup installation for homes that flood during power outages.
- Emergency Sewer Backup ServiceEmergency clearing of blocked sewer lines and main line backups, including camera inspection to identify the underlying cause.