Read Also

Shallow well jet pumps are used for wells that go down to a depth of 25 feet while deep well jet pumps typically go down 150 feet. Deeper wells would require a submersible pump (McDonald) .

Jet pumps are placed above ground and lift water from the ground through a suction pipe which creates a vacuum with an impeller that drives water through a small nozzle. Because jet pumps use water to pump water, they first need to be primed with flowing water.

The well pump, or water pump, is the heart of the system. It is what pumps water upward and into the household or designated water system. The two most popular types of pumps used today are jet pumps and submersible pumps . Both pumps rely on centrifugal force in order to force water upward. Spinning rotors, known as impellers, create a vacuum which forces water upward through the well casing and into the distribution system. The type of pump required for a well system would depend on the depth of the well and the amount of water required for the household.

Submersible pumps are cylindrical in shape, housing the pump motor and a series of impellers which drives water up the pump into the drop pipe. Because of their efficiency, durability, and versatility in well depth, most modern well systems use submersible pumps over any other pump (McDonald) .

Submersible pumps have a much wider range in depth and can be used in wells as shallow as 25 feet and as deep as 400 feet. As the name implies, submersible pumps are submerged deep in the well just under the water level. Most of its energy is dedicated to pushing water upward rather than sucking water from above as in the case with jet pumps.

Pressure tanks are used to maintain water pressure throughout the distribution system and to store a reserve water supply so as to relieve the pump of continuous usage. The sizes range from around 40 gallons for domestic use to 21, 000 gallons or more for industrial use. In conventional pressure tanks, pressure is created by pumping water into the tank until air in the tank is compressed to typically 40, 50 or 60 psi (pounds per square inch). An air compressor ensures that the air pressure is maintained. When the valve is opened via a tap, the air pressure in the tank forces water out of the tank and into the pipes for distribution.

Pressure Switch & Control Box

Well pumps, especially submersible pumps, are not meant for around the clock usage. Continuous usage would cause unnecessary wear on the pumping mechanism and would rack additional electricity costs. The pressure switch and the control box work in conjunction with the pressure tank to measure the water pressure in the well system so that the pump is only used when the water pressure drops below a certain level.

Typical well systems have a water pressure range of 40-60 psi. When the water pressure drops below 40 psi, the pressure switch turns the pump on, bringing the water pressure back up within range. When the water pressure is at an adequate level, the pressure switch turns the pump back off.

Casing

Well casing, usually made of carbon steel, stainless steel or polyvinyl chloride (PVC), is a tube-shaped structure placed in a well to maintain the well opening spanning from the target ground water to the land surface. The casing prevents dirt from contaminating the water and keeps excess water out of the well. It also keeps out contaminants from less desirable groundwater. Some may use concrete, fiberglass, or asbestos cement to build well casing. However, the choice of material depends on the geologic formation. For example, steel is used where hard rock lies underground.

Well Cap

Well caps are placed on top well casing to keep out debris, insects and small animals. They are usually made of aluminum or plastic, and they include a vented screen to equalize the pressure difference between the inside and outside of the well when water is pumped from the well. To prevent overflows from contaminating the well, the cap should extend past flood level.

Well Screen

Well screens are filtering devices attached to the bottom of the well casing to prevent excess sediment from contaminating the well. Continuous slot, slotted pipe, and perforated pipe are the most popular well screens used. Well screens are built to suit the geologic condition with specified openings and holes to match the screen filtering capability. They are also designed to be placed within the saturated portion of the aquifer to prevent damage if the groundwater elevation drops.

Pitless Adapter

Older well systems required that a large pit be dug in order that pipes were placed far enough underground so that they wouldn't freeze during winter time. But the pit design has proven to be quite hazardous and prone to contamination.

The modern pitless design allows for the casing to reach all the way up to the ground level. Pitless adapters are connectors that provide a sanitary seal between the well casing and the waterline. They are connected to the well casing below the frost line to divert water horizontally, preventing the water from freezing. A check valve may be fitted below the adapter to prevent water from flowing back into the well.