Sump pump

A small submersible AC sump pump with a garden hose connector

A sump pump is a pump used to remove water that has accumulated in a water-collecting sump basin, commonly found in the basements of homes and other buildings, and in other locations where water must be removed, such as construction sites. The water may enter via the perimeter drains of a basement waterproofing system funneling into the basin, or because of rain or natural ground water seepage if the basement is below the water table level.

More generally, a "sump" is any local depression where water may accumulate. For example, many industrial cooling towers have a built-in sump where a pool of water is used to supply water spray nozzles higher in the tower. Sump pumps are used in industrial plants, construction sites, mines, power plants, military installations, transportation facilities, or anywhere that water can accumulate.