What a sump pump does and where it lives

A sump pump sits in a pit dug into the lowest point of a basement or crawlspace floor. Groundwater that seeps in through the foundation, or rainwater that drains down from the yard, collects in that pit. When the water rises to a set level, a float switch triggers the pump, and the pump pushes the water out through a discharge line that empties away from the house. The goal is to keep the space below your living area dry before moisture can do damage to the structure, the insulation, or anything stored down there.
In the East Bay the setup is a little different from wetter climates. Many homes here sit on a concrete slab with no basement at all, so a sump pump is less common than in the Pacific Northwest or the Midwest. Where they do appear in our area, it is usually in homes with a crawlspace, in properties that sit at the base of a slope where runoff concentrates, or in older homes with older grading that lets water pool near the foundation. When the first real storm of the season arrives after a long dry summer, the ground is hard and water sheds quickly, and a crawlspace without a working pump can take on several inches of standing water in a matter of hours.


