March 3, 2003

Private Wells

Over three hundred Walpole residences are serviced by on-site private wells, and many of those wells serve as primary drinking water sources. The Walpole Board of Health regularly receives inquiries from homeowners seeking information on converting from public to private water supply.

Jurisdiction over private drinking water well installation and activation lies with a local Board of Health. Walpole regulations require that before a private well is initially put into service, it must be tested for a variety of parameters including volatile organic compounds (VOCs) and heavy metal toxicity. Water quality must conform to Federal and State standards before being approved for domestic water use. Testing includes many common yet potentially dangerous contaminants found in groundwater. After a well is approved and placed in service, the responsibility for future testing lies with the well owner. Public water supplies are routinely tested for bacteria and a variety of chemicals, and they must meet Federal Safe Drinking Water standards. Most private well owners, however, fail to recognize the need or importance of testing their own water source. They need to understand that many chemicals, depending on their levels, are potentially dangerous. Many chemicals are colorless, odorless, and have no taste.

The other type of private well in Walpole is the irrigation well, most commonly used by homeowners to water lawns, gardens and to fill swimming pools. These wells do not have regulated testing requirements, but homeowners should seriously consider testing an irrigation well. Swimming in contaminated water causes skin contact with the contaminants. High levels of trace metals may accumulate on vegetables in a garden. How often do you see someone quenching his or her thirst from a garden hose?

After initial testing, the sampling frequency depends upon individual circumstances as does what substances to look for. A prospective homebuyer should test for all contaminants in a private drinking water well before purchasing a home with one. Bacteria and nitrate/nitrite should be looked for yearly. Most other contaminates can be sampled every ten years, unless an earlier test found elevated contaminate levels. Other triggers for more frequent testing includes recent well repairs, wells in areas where high levels of hazardous chemicals are handled, or a noticeable change in your water quality (taste, appearance, odor). The Department of Environmental protection recommends that samples be taken after heavy rainstorms. Water analysis should be done by a Massachusetts state certified lab. Results will reveal levels of any substances found in your water. If they exceed safe drinking water standards, steps should be taken to alleviate problems. Various remediation methods are available depending upon the situation.

For any questions or concerns regarding on-site private wells, please call your Board of Health agents at 508-660-7321