Well pumps are used to draw water from a depth where the water table is several feet beneath the area of application. Typically used for water abtraction or delivery, there are two main types of well pumps: jet pumps, and submersible pumps. While both styles have their benefits, read further to determine the type you need for your application.Select Your New Well Pump »
Jet pumps are mounted above the well, either in the home or in a well house, and draw the water up from the well through suction, and because suction is involved, atmospheric pressure is what's really doing the work. These days, the most common pump for a shallow water well pumping is a jet pump. As the pressure builds, you create a vacuum in the tube above the water. Once the vacuum is there, the weight of the air, or atmospheric pressure, pushes the water up the straw. Consequently, the height that you can lift the water with a shallow-well jet pump relates to the weight of the air. While air pressure varies with elevation, it's common to limit the depth of a jet-pump-operated shallow well to about 25 ft. Because shallow-well jet pumps use water to draw water, they generally need to be primed-filled with water-before they'll work. To keep water in the pump and plumbing system from flowing back down into the well, a 1-way check valve is installed in the feed line to the well pump.
To pump out water a little deeper than 25 ft., there must be some basic modifications to your water well. It simply involves separating the jet from the motor and impeller housing and placing the jet assembly down in the water as illustrated here in the Double-Drop Jet-Pump System well pump diagram. In a typical deep-well jet-pump configuration, one pipe mounted to the impeller housing drives water down into the jet body that's located about 10 to 20 ft. below the minimum well water level. A second pipe connects the output side of the jet body back to the well pump.
At the jet, the increase in water velocity creates the partial vacuum that draws standing well water into the second pipe and then back into the pump and plumbing system. Deep-well jet pumps use both the suction at the jet to bring water into the system and pressure applied by the impeller to lift the water.
Like shallow-well systems, a jet pump in a deep-well system needs to be primed to operate. A foot valve at the bottom of the well piping prevents water from draining from the pipes and pump. Jet pumps that have two or more impellers are called multistage pumps.Select Your New Well Pump »
A submersible pump is characterized by a long cylindrical shape that fits inside the well casing. The bottom half is made up of a sealed pump motor that is connected to the aboveground power source and controlled by wires. The actual pump half of the unit is comprised of a stacked series of impellers-each separated by a diffuser-that drives the water up the pipe to the plumbing system. Unlike a jet pump drawing water from above with pressure, the submersible applies pressure below to push the water upward! This also eliminates the need for primer water to be present, unlike the jet water well pumps. This type of pump is useful for deeper well, and with constant pressure applications.
In modern installations, the well casing outside the home is connected to the plumbing system by a pipe that runs beneath the ground to the basement. This horizontal pipe joins the well pipe at a connector called a pitless adapter. The function of the adapter is to permit access to the pump and well piping through the top of the well casing, while routing water from the pump into the plumbing system.
While submersible pumps are more efficient than jet pumps in delivering more water for the same size motor, pump or motor problems will necessitate pulling the unit from the well casing-a job that's best left to a pro. However, submersibles are known for their reliability and often perform their role 20 to 25 years without servicing. Submersible pumps may also be used in shallow water wells. However, silt, sand, algae and other contaminants can shorten the pump's life.Select Your New Well Pump »