How Does a Submersible Water Pump Work?

Katherine Bostick

A submersible water pump operates beneath the earth’s surface. A submersible water pump will not operate if it is not submerged in liquid. A submersible water pump pushes water to the surface, instead of sucking the water out of the ground like above ground water pumps.

What is a Submersible Water Pump?

Most submersible pumps are long cylinders that are about 3 to 5 inches around and 2 to 4 feet long. Submersible water pumps have a hermetically sealed motor that is close-coupled to the body of the water pump. Having a hermetically sealed motor prevents the water from getting inside the pumps motor and causing a short circuit. Other components of a submersible water pump are the cable, which is connected to the motor, and a pipe that transports the water to the surface of the well.


Above ground water pumps have a higher rate of mechanical problems because they have to pull water up out of the well, whereas a submersible pump has fewer mechanical problems, and can last up to 25 years before needing to be replaced. An above ground water pump can suffer from a problem called cavitation, which is a common mechanical problem caused by the high elevation of the water pump compared to the surface of the water. Submersible water pumps do not get damaged due to cavitation because they are usually deep beneath the surface of the water.

Bringing Water to the Surface

When the pressure switch comes on, an electrical current is sent down an electrical wire to the submersible water pump. Impellers contained within the body of the pump start turning. The rotation of the impellers sucks water into the body of the pump. The impellers then push the water out of the pump and up through the pipe to the water tank. When the pressure switch cuts off, the current stops operating the submersible water pump, the impellers stop turning, and the water is no longer pushed to the surface by the pump.