Sump pumps can fail for a variety of reasons. Most commonly, they can lose power during an outage. The sump pump motor can also burn out and the pump can become clogged or misaligned. Or, the sump pump float switch might get stuck or tangled.Sump pumps can also fail if the sump pit isn’t large enough to accommodate the pump or if there’s too much water for the pump to handle. You might also have a sump pump that was incorrectly installed or that breaks down from improper maintenance.