Sewage pump includes a motor, a main shaft, an upper impeller, a lower impeller, a grinding wheel, a top cap, an upper bearing base with an upper mounting plate, an upper bearing base, a tube body with a wire inlet connector, a lower bearing base, a lower bearing with a lower mounting plate, a lower base and a vertical bypass. The main shaft has a quad-bearing structure to minimize deflection at high speed and high pressure and has rotary seals at each end to improve stability and sealing efficiency. Moreover, the wire inlet connector is filled with epoxy filling material to protect the wire, and the sewage pump further has moisture-sensors to timely stop the motor when sealing efficiency is failing.