Introduction to water well pumps

In many parts of the country, where a municipal water main is inaccessible, or comes with a high price tag, home owners use groundwater as the primary source of water supply. Groundwater is accessible through specially drilled wells and is transported to the surface through the use of well pumps.

Based on specific needs and applications, well pumps are available in a multitude of types, sizes, mounting and installation options, performance capacity, and pumping methods. Prior to choosing a pump the following factors should be known: purpose of the well (domestic water supply, irrigation, etc), water level, diameter of the shaft, amount of water that needs to be pumped (measured in gallons per minute), as well as depth of the well.

There are two most common types of well pumps: submersible deep well pumps and non submersible jet pumps.

  1. As its name implies, a submersible deep well pump is installed within the underwater part of the well. The pump can be used in wells as deep as 500 feet and water is delivered to the surface through an inserted pipe

    The pump consists of two parts, the first of which holds a hermetically sealed electric powered motor, which is wired to electricity source that is located outside the well. The second part of the pump consists of impellers. When the pump is turned on, the motor spins the impellers, which in turn create the pressure to push the water upward to the surface.

    The amount of pressure that a pump needs to exert is directly correlated to the length of the pipe that connects it to the surface; the longer the pipe, the more pressure is required to lift the water up. Submersible deep well pumps are known to be durable with a life cycle of up to 25 years.

    Little Giant and Grundfos produce a wide array of submersible deep well pumps.

  2. Unlike a deep well pump, a jet pump is not submersible and is installed in close proximity to the well, with a pipe inserted into the shaft of the well (below water level).

    Jet pumps come in two types: shallow well jet jumps and convertible jet pumps.

    The optimal well depth for a shallow well jet pump is up to 25 feet. The pump uses the suction method to transport water to the surface and consists of a centrifugal pump and a jet ejector (made up of a nozzle and venturi). There is also a 1-way check valve, to keep water from flowing back.

    In cases where water level is below 25 feet or can fluctuate, a convertible jet pump (also referred to as deep well jet pump) is utilized, which allows the pump to be used in wells that are up to 90 feet deep. In a convertible jet pump, the injector is installed inside the well, below the water level.  There are two pipes that connect the ejector inside the well to the pump.

    Aside from injector location, both types of jet pump function very similar - once a jet pump is turned on, the impeller (centrifugal pump) moves water through a nozzle-like jet, which increases speed of the water flow. As the water speeds through the jet, a vacuum is created, which causes the water from the well to flow to the surface. Once it’s pumped, most of the water goes into the water tank, while a smaller amount is sent back to operate the jet.

    Due to the fact that water is needed to operate the jet, the pump needs to go through a process called priming, which involves filling the pump with water prior to it being used for the first time. Jet pumps produced by Grundfos are self-primed, while those produced by Little Giant are not.