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Well Basics

If you don't get your water from a municipal water source, it probably comes from a private well. A basic well includes a water source -- typically at least 100 feet deep to prevent contaminated drinking water; a casing pipe that is 4 to 6 inches in diameter lines the interior of the well. The casing extends out of the ground at least 12 inches and is capped to prevent contamination. Water is pumped from the source with a submersible pump that is usually about 10 feet from the bottom of the well to a pressure tank in or near the house. The tank, in turn, feeds the water supply lines.

In a standard pressure tank, incoming water forces air into the upper third of the tank, where it forms a spring-like cushion. When the air pressure reaches a preset level -- usually between 50 and 60 pounds per square inch (psi) -- the spring action of the compressed air triggers a pressure switch, which shuts off the pump. As water is drawn from the tank, pressure diminishes. When it reaches a preset level -- 30 to 40 psi -- the switch turns the pump on again.

When the pressure tank loses too much air pressure, it can become "waterlogged." This causes the pump to switch on and off frequently. This problem can be solved by turning off the power to the pump and attaching a garden hose to the drain valve at the bottom of the tank. The valve should be opened and remain open until there in no more pressure in the tank. A faucet must then be opened in the house to drain all of the water out of the tank. After the tank is empty, turn off the faucet, close the drain valve on the tank, remove the hose, and turn the pump back on.

A leaking tank is another prevalent problem. If a leak develops, it usually appears first as an oozing rusty blemish. Although tank plugs are available, they are only a temporary measure. The tank should be replaced as soon as possible.

Occasionally, the pump may stop working. If this is the case, first check for a blown fuse or tripped breaker. A loose wire may also be the source of the problem. If all of these check out, your best bet is to call in a well service technician.