The function of a sewage pump is to move sewage liquids and solids between one location and another.  Typically, in residential applications, sewage (including soft solids up to 2” in diameter) is pumped from a sewage basin to a sewer system or a septic tank.  A sewage pump is installed at the lowest point of the sewage basin.  The basin itself is placed at or below the floor level of the basement.

Since the pump is submerged most of the time, it is also referred to as a submersible sewage pump. Sewage pump can be automatic, manual or dual (piggyback) mode.  Manual pumps need be manually turned on/off as the need arises.  Automatic pumps have a floating switch, which turns the pump on and off whenever sewage in the basin reaches a certain (usually pre-set) level.
A dual mode pump contains a piggyback plug, which allows the pump to be used as either manual, wherein the pump bypasses the switch and is plugged in directly into the socket or as automatic, wherein the pump is plugged in through the floating switch and works only when the switch is activated.

Due to a possibility of sewage overflow, it is generally not advised to use a manual sewage pump inside of a sewage basin.

Sewage pumps are centrifugal pumps, with special design considerations enabling solids to pass without clogging the pump.  When the pump is turned on, the motor starts to rotate the impeller, creating the pressure that pushes water into the impeller and from there into the discharge pipe.