Well Pumps

What is a well pump?

A well pump is used to draw water from an underground water source, normally a drilled borehole well. They may also be used to pump out a dug well, or to move fluid from an underground cavern. Well pumps have a variety of applications, with the two most common ones being to bring ground water to the surface for irrigation and to bring drinking water from underground. They are used to supply water for both turf irrigation and agriculture irrigation.

Well pumps are used for drinking water supply and are also used in many private homes that are remote from central water supply systems. They are often used to provide industrial plant make-up water for process or cooling, or to provide fire water for industrial plants. In some cases these pumps are used to remove water from the perimeter of mining sites, landfills, and service stations. Others can be set up to monitor the water as it is pumped to ensure that hazardous materials are not migrating underground.

How do they work?

Original well pumps were reciprocating pumps, using manual action or a motor to push and pull a long rod with a series of check valves to gradually bring water to the surface. These have mostly been replaced with jet pumps, submersible pumps, and vertical turbine type pumps.

Types of well pumps

The type of well pump needed to draw water from a well depends mainly upon the depth of the water table and the flow rate and pressure (head) required. Jet pumps are most commonly used in residential and small commercial applications, and where the water table is near the surface. A jet pump motor is mounted inside the pump house, and it uses an internal centrifugal pump with an eductor or ejector to create a vacuum. This causes water from the well to rise up a tube in the well and fill the void created by the vacuum.

For areas where the water table is deeper, submersible pumps are generally used. This pump consists of a sealed pump and motor that sits in the water at the bottom of the well, a long pipe that conveys the water to a storage tank at grade level, and a protected wire that connects the motor to an aboveground power source. Submersible pumps are generally able to handle higher flow rates than jet pumps, but since they sit so far below the ground, they are difficult to service and usually require a specialist. They are quieter than jet pumps, since the motor is located at the bottom of the pump, and they don’t require any type of shaft seal.

For higher flow applications than can be accommodated with submersible pumps, vertical line shaft turbines may be used.