Your drainage system only requires a sump pump if the weeping tile system installed has no other gravity fed drainage source. In some locales, sump pumps are also required by the Building Code. Sump pumps are installed in a gravity fed “pit”, once the water level rises to a certain height, the sump pump automatically turns on and discharges the water outside of the house to the exterior grade. Sump pumps are electrically powered, and sometimes need battery backups. A rainstorm that’s strong enough to cut your electrical power is definitely the kind of storm that will fill the pit and require it to be working during such time.