Whether you are building a home or drilling an additional well to cope with a dwindling water supply, you need to be sure your drinking water is safe. The most important thing you can do to ensure the quality of your drinking water, besides proper drilling and construction techniques, is to choose a safe location for your well.

Well water is drawn from the underground aquifer, which is recharged by rainwater slowly traveling through the ground. It is filtered by the soil and rocks, which remove many contaminants. However, some dangerous contaminants make their way through, and some aquifers do not filter as well as others. When planning for a new well, you need to locate it far from sources of natural and chemical contamination.

Natural Contamination

For homes that are not connected to public sewer systems, the most common source of natural contamination is the septic system, including the leach field. The concentration of waste in the septic system is too high for the ground to filter out effectively, so dangerous microbes and bacteria will enter the well water. Other sources of contamination are livestock feedlots, manure piles and fertilizer storage areas. Anything that involves human or animal waste could contain the E.coli and Campylobacter bacteria, among other disease-causing organisms. According to the Center for Disease Control, wells should be at least 50 feet from septic systems, 100 feet from fertilizer storage sources, and 250 feet from manure sources to reduce the risk.

Chemical Contamination

The most common chemical contaminants in residential water wells are petroleum products, pesticides, chemical fertilizers and household wastes. Petroleum products can enter the water supply from leaking tanks and equipment on or near the property. Cars that leak gasoline, motor oil and other fluids deposit these substances on roads. Each time it rains, the contaminated runoff seeps into the ground and is transported through the aquifer. The CDC also recommends that wells be drilled at least 100 feet from petroleum tanks and 20 feet from public roadways.

In rural areas pesticides and chemical fertilizers are common contaminants near large farms, and it's a problem if the water in your aquifer flows toward you. Dangerous household waste includes automotive batteries that contain lead and mercury, lead-based paint, cleaning products, solvents and many other substances. While these are not problem for most homeowners, it can be if these items were ever stored or dumped on the property. The well driller you choose should take the history of the property into account to determine if any of these items were stored there.

Experienced well drillers recognize these hazards and are familiar with state and federal regulations for siting wells. They are also familiar with the geological features that could also be dangerous. For example, the harmful gas radon is common in underground granite formations and is released by drilling. Radon can be removed from drinking water, but a well driller may recommend against putting the well in that location.

You may not be able to drill your new well in the most convenient place, however, the health and safety of you and your family is more important. Talk to your well driller, such as Henderson Well & Pump Co., about your property's history as well as your future building plans so they can find the safest place for your well.