The water we drink originates from either surface water bodies or from groundwater. Groundwater comes from natural underground layers, consisting of sand or gravel that contains water. These formations are called aquifers. The land area that can have an impact on the quality of this underground water is called a watershed. The groundwater used for drinking may travel long distances underground before it is pumped from a well and distributed through pipes to homes and businesses.
Groundwater is naturally filtered as it passes through layers of the earth and into underground aquifers. Water that supplies wells generally contains less organic material than surface water and may not need to go through any or all of the treatments needed for surface water sources. The quality of the water depends on local conditions.
When rainwater travels overland as runoff and downward into the ground, it can become contaminated. The risk of groundwater contamination is greater in developed areas, where water has the potential to come in contact with pollutants as it travels toward drinking water wells. Generally speaking, the closer the source of contaminants, the greater the risk. Certain pollutants such as nitrates, road salts, pesticides, bacteria, organic compounds, improper disposal of hazardous materials and metals are recognized as water pollutants. Consequently, land activities near a drinking water well that use or store these materials have the potential to threaten a water supply.
How Does Needham Protect the Water Supply
In 1992, Needham adopted zoning bylaws and health regulations to ensure the highest quality of water delivered to residents, businesses and institutions. These ordinances are designed to preserve the existing and potential sources of drinking water supplies, conserve the natural resources of the Town and to prevent contamination of the environment.
The Town of Needham developed a Department of Environmental Protection approved water supply protection strategy based on land use and operational restrictions in areas of particular influence to the drinking water wells. The area of primary interest to the protection of water quality is known as the Zone II or recharge area that contributes water to the wells either through the ground of via surface drainage.
How You Can Help Protect Our Water Supply
View information from the Environmental Protection Agency (EPA) on citizen involvement in Water Supply Protection (PDF)