How a Private Well Works
Starting from the precipitation phase of the Hydrologic Cycle, the water that is absorbed into the earth drips down into underground aquifers. These aquifers are not large, open caves beneath the earth's surface, but instead they are layers of rock and sediment and soil that water slowly drips through. Gravity works by pulling the surface water down through the rock and soil deep into the layers of earth. Once the water drips past the initial layer, it then saturates the deeper soils. The top layer of soil that is left drier and doesn't necessarily carry any fresh water is called the water table.
Although the United States has one of the safest drinking water supplies in the world, there are still many contaminants that can infiltrate ground water that flow to wells. Most are naturally occurring minerals and chemicals (such as radon and arsenic). However, local land use practices can also bring in pesticides, chemicals from farms and contaminants from malfunctioning waste-water treatment systems.
Radon is a naturally occurring gas that is produced by the breakdown of uranium in soil, rock and water. From there it can dissolve into a water supply.
Groundwater that flows through granite or granitic sand is often found to have a higher level of radon than other areas. Radon becomes more of a problem when showering, washing dishes and doing laundry as the steam from the hot water used releases the radon gas into the air.
Radon has been shown to increase the risk of developing stomach or other internal organ cancers. A whole house carbon filter is the best way to remove radon from water.
Arsenic is also a naturally occurring element in rocks and soil. It usually enters the water from natural deposits in the earth near an underground aquifer. There is a popular belief that when water levels drop significantly, arsenic dissolves out of certain rock formation below the earth.
Arsenic is similar to Radon in the way that it is more harmful in water vapor and as a gas than in water alone. Arsenic has been linked to bladder, lung and skin cancer and also has effects on the nervous system. It may also cause birth defects and reproductive problems.
One of the best ways to filter out Arsenic is with an RO Filter or through distillation.
Chemicals used in farming and other agricultural practices are one of the most dangerous contaminants for well owners. Farms that use pesticides, herbicides and other man-made chemicals almost always end up contaminating ground water around their own land and even land that is miles away.
Once chemicals are used, anything remaining on plants or on the surface ground water level becomes mobile through snow and rain. The precipitation pushes the water and chemicals through the ground water and then it infiltrates the aquifers below the earth. From there the chemical flows into water supplies and gets pumped up through wells into resident's homes.
Water travels quite a distance and sometimes the chemicals and pesticides used in farming can end up miles away just by the flow of water.
Well Water Test Kits