A sump pump sits in a pit at the lowest point of a basement or crawl space and activates automatically when water reaches a certain level, and pumps it away from the foundation to prevent flooding. Most units last seven to ten years, depending on how often they cycle and whether they've been properly maintained. Signs of a failing sump pump include unusual noises during operation, visible rust or corrosion, and water in the pit that isn't being cleared as quickly as it should be.
