A typical corrosion-resistant sump pump uses a centrifugal pump to move water. When the motor is turned on, it turns a spiral or sector device called an impeller. Using centrifugal force, the rotating impeller forces the water towards the side of the pipe, creating a low pressure region at its center. The water from the pit rushes into the gap, and the rotation of the impeller pushes it out of the pipe.
Corrosion-resistant sump pumps are powered by electricity and use standard household currents, so they do not require dedicated wiring outside the grounded outlet. Since the corrosion resistant sump pump is always in or near the water, it is best to install a ground fault circuit breaker (GFCI) at the water outlet to prevent accidental electric shock.
There are two main corrosion resistant sump pump designs, both about 2 1/2 to 3 feet (76.2 to 91 cm) high.
The diving corrosion resistant sump pump is installed in the water. It is housed in a waterproof enclosure with the pump itself at the bottom and the outlet tube near the top. A flat plate or grille covers the bottom of the pump to prevent debris. When the pump is turned on, water is drawn through the grate and into the pipe and out of your home.
Another common type of corrosion resistant sump pump is the base pump. The base pump looks like a long stick with a fat head. Even if the pit is full, the pedestal can keep the pump away from the puddle and away from the water. The inlet tube extends down into the bottom of the pit to draw water out. Since the motor and pump are not in the water, the base pump is usually louder than the submersible pump - but it is cheaper.