Storage-Pressure Tanks

Standard Tank: tank without a bladder or diaphragm - This storage tank is normally made of galvanized metal.  It has a pressure gauge and valve on the top for pumping air into the tank. Compressed air in the tank is what creates pressure in the system. Air is compressible, but water is not. The life expectancy of a galvanized water storage/pressure tank is approximately 18 to 22 years. These tanks are generally found in older systems; very few are discovered in modern housing.

Diaphragm Tank: tank with a bladder or diaphragm - A diaphragm tank is a storage/pressure tank that functions the same way that a standard tank functions, however, it has a diaphragm or bladder that keeps the water and air separated. This is the most common type of tank.

Cistern - A cistern is a storage tank. It is typically used to hold rainwater for irrigation, hold water  situations where the well does not produce water fast enough, or hold water that is trucked in, probably due to poor water conditions or supply at the site.  Generally, cisterns are not covered; this creates concerns for insects, debris and dust that  may affect the water.

Well Head - The well casing is normally a 6-inch steel or PVC pipe with a cap that is sealed. The head for all modern wells should be 18 inches above grade to prevent the infiltration of surface water. The well is drilled 5' to 10' into solid bedrock, then the casing is grouted with a slurry of 5% bentonite and 95% cement. These procedures are necessary to provide a proper base, stabilize the well and keep water from entering the casing from the bottom. Lightweight steel pipe is 13 pounds per foot; medium weight pipe is 15 pounds per foot; and heavy weight steel pipe is 19 pounds per foot. The PVC piping is a thick-walled pipe, designed for wells. State or local authorities dictate the piping that may be used.