What is a sump pump?

A sump pump sits in a basin (sump pit) at the lowest point of a basement or crawlspace and removes water that collects from groundwater seepage, heavy rain, or drainage systems. When water rises in the pit and triggers a float switch, the pump activates and pushes the water up through a discharge line and away from the foundation, typically to the street, storm drain, or daylight outlet.

Two main types serve different roles. A primary pump, usually 3/8 to 1.5 horsepower, runs on household electricity and handles routine water removal. A battery-backup pump activates when the primary pump fails or during power outages, giving homeowners protection during the heavy rainfall and storms when flooding risk is highest. The backup pump is typically smaller and powered by a rechargeable battery.

Sump pumps matter in Columbia because basements and crawlspaces are vulnerable to water damage from both seasonal groundwater and storm surge. Without a pump, water intrusion can lead to mold, foundation strain, and structural damage. A well-maintained primary pump with battery backup provides reliable defense against both everyday seepage and emergency flooding.