Early in architectural history, the sump pump was created to keep foundations, basements and cellars dry from flood waters, and low water planes.  They were originally used in the New England and Great Lake states where water is prevalent more closer to homes.  However, over the many years of home building near rivers and other flood planes has created a greater need for these pumps to be installed in more homes to keep them dry year round from gathering ground water and overflow rain water that can accumulate in the sump pits.  The sump pumps take the excess water and return them to the proper channels to be treated within the city treatment plants.