Well Basics
Up to twenty percent of American households rely on private wells for their water. A well is made by reaching ground water in the water table. Ground water is stored naturally below the earth’s surface. Most ground water originates as rain or snow that seeps into the ground and collects.
There are three different well designs in common use, and each design consists of three parts: The well pipe, the pump and the storage tank. Although wells are generally dependable, they can act up.
The oldest type of well, the piston pump, has rarely been installed since the 1950’s, but many are still in service. This classic style is driven by a windmill-or by a hand-operated pitcher mechanism. The piston, submerged in the well shaft below water level, is connected to a rod that extends up the well casing.
The jet pump is the most common design of a shallow well. It creates a vacuum to draw water up a well. Jet Pumps are defined as either a single-drop pipe pump or a double-drop pipe pump. The single-drop jet pump is limited to wells roughly 30 feet deep-but less at higher elevations, where air pressure drops. A double drop pump can lift water from 100 feet or more, because the surface impeller directs a portion of its water back down the second pipe (hence the term “double-drop”). The water passes through an ejector at the bottom, which creates more pressure and lift in the suction pipe. This type also needs a continuous prime to work: when the pump is turned on, the prime water is pushed through the impellers and new water is pumped up behind the prime.
For a deeper well, a submersible pump can be suspended directly in to the aquifer. The pump’s electric motor is sealed and the impellers simply push water up the pipe and into your house. A submersible pump can reach very deep aquifers, and it is considered to be nearly problem-free. A submersible pump may perform without servicing for 20-25 years, but it has a major drawback: if the pump motor burns out, a truck-mounted derrick is required to retrieve it. Submersible pumps may also be used in shallow wells, but silt, sand, algae and other contaminants can shorten the pump’s life.
No matter what kind of system you have the components on the output side of the pump are all similar. A well pump is not intended to run continuously and doesn’t start every time you open a tap.
Your well almost certainly has a galvanized steel pressure tank, with a pressure switch, pressure gauge and drain valve attached to the tank or mounted nearby. Whenever the system is activated, water is pumped up into the tank from the ground, compressing the air in the tank. When the air pressure reaches a dermined threshold, the well pump shuts off. This air pressure provides the force needed to push the water from the tank into the fixtures. Once the water in the tank drops enough to reduce the air pressure to a predetermined level, he pump starts up again and begins to draw additional water.
