Last time we talked about septic systems. Chances are if you live outside an area served by central sewers and have a septic system for your on-site sewage disposal system, you may also have a well for your water supply. Here's some information on water supply wells.

It's pretty obvious that we need water for a wide variety of uses around the house-uses that range from drinking and cooking to washing clothes, dishes and even ourselves!

Did you ever stop to think just how much water you use in an average day? The U.S. Environmental Protection Agency places the volume at between 50 and 75 gallons per day per person in a single-family dwelling. The New York State Department of Health allocates about 65 gallons per day per person in a house with water conservation plumbing fixtures, while 75 gallons per day is the volume used for a dwelling that has older, non-conservation fixtures. In any event, we all depend upon an ample supply of fresh, clean water.

While there are a variety of well construction methods and configurations, many new, modern wells in our area are drilled with a rotary drill. A steel pipe casing extends down within the drill hole to a suitable level to provide a conduit to water of sufficient quality and quantity. The casing also prevents shallow, possibly contaminated, water from entering the well between ground level and the level of the water-bearing geological layer (also known as the "aquifer"). Additionally, a grout seal is pumped into the space around the outside of the casing to prevent surface water (that could be contaminated) from following the casing down to the level of the aquifer. Finally, a well cap and seal are installed to prevent contaminated water or other materials from entering the well.

Depending upon the surrounding strata, a screen may be installed at the bottom of the casing to prevent sand or other fine materials from being drawn into the well.

A submersible pump is installed at the bottom of the well to pump water from the ground to the house.

In many household water supply systems in our area, the submersible pump conveys water to a pressure tank inside the house. When water pressure drops inside the pressure tank due to water usage inside the house, a pressure-sensitive switch on the tank turns the submersible pump on, supplying additional water to the system.

It's obvious from the above description that a variety of precautions are taken during construction of the well itself to avoid contamination. In addition, care should be taken in providing adequate separation between a well and septic systems, runoff diversions, and other possible sources of contamination.

With proper construction and subsequent care, a well will provide you with an ample supply of fresh, pure drinking water.