A sump pump's generally used in basements, especially those where the water table is really high.
the basement is so low that water can leach from the ground into the basement through minute cracks as the groundwater level rises.. and it can flood.
A sump pump bump (agh! cant keep my sump, pump, and bump straight!) is set in a hole in the basement floor which ends up being the lowest place in the basement. (Thus the place where water collects first). The pump forces water out of this hole out a pipe away from the house, protecting the basement.
If the pump fails then that hole will eventually overflow and water will start pooling on the floor in the basement.
Anyway, enough about bumping sump pumps, eh?
