A sump pump is a small pump installed in the lowest part of a basement and crawlspace. Its job is to helo keep the area under the building dry and to prevent it from flooding. Sump pumps are usually installed in specially constructed sump pits. Water flows into the sump pit through drains or by natural water migration through the soil. The sump pump's job is to pump the water out of the pit and away from the building so the basement or crawlspace stays dry. According to the American Society of Home Inspectors, more than 60 percent of American homes suffer from below-ground wetness [source:Basement Systems].