According to Wiki:
A sump pump is a pump used to remove water that has accumulated in a water collecting sump basin, commonly found in the basement of homes. The water may enter via the perimeter drains of a basement waterproofing system, funneling into the basin or because of rain or natural ground water, if the basement is below the water table level. Sump pumps are used where basement flooding happens regularly and to remedy dampness where the water table is above the foundation of a home. Sump pumps send water away from a house to any place where it is no longer problematic, such as a municipal storm drain or a dry well.
I remember a friend who happened to have a basement at home, every time the rain pours hard they will be in problem as to who will do the cleaning/funneling of the water from the basement because they don't own a sump pump. Good thing, finding a sump pump at wegotpumps.com is the best remedy they have mind because they were able to find great deals and able to get one. Now, it's kinda' hassle-free for them every time it rains! :)