Private well water should be tested yearly, and in some cases more often, according to new guidance offered by the American Academy of Pediatrics (AAP). Researchers at the National Institute of Environmental Health Sciences (NIEHS), part of the National Institutes of Health, took a lead role in working with the AAP to develop these recommendations and draft a new AAP policy statement about the things parents should do if their children drink well water. The recommendations call for annual well testing, especially for nitrate and microorganisms such as coliform bacteria. The recommendations point out circumstances when additional testing should occur, including testing when there is a new infant in the house or if the well is subjected to structural damage.

"Children are especially vulnerable to waterborne illnesses that may come from contaminated wells," says Walter Rogan, M.D., an epidemiologist at NIEHS and lead author on the policy statement and technical report that appears in the June issue ofPediatrics. The new policy statement, "Drinking Water from Private Wells and Risks to Children," offers recommendations for inspection, testing and remediation of wells providing drinking water for children.

"With few exceptions, well owners are responsible for their own wells," says Rogan. Private wells are not subject to federal regulations, and are only minimally regulated by states.

Nitrate is the most common contaminant in wells. The presence of nitrates can be a problem particularly for infants under 3 months who cannot metabolize nitrate. Water with a nitrate concentration of more than 1.0 milligrams per liter should not be used to prepare infant formula or given to a child younger than 1 year. The policy statement suggests using bottled water for infants when nitrate contamination is detected, or when the source of drinking water is not known.

The policy statement and accompanying technical report point out that water contamination is inherently local, and that families with wells need to keep in contact with state and local health experts to determine what should be tested in their community. For example, some parts of the country may have arsenic, radon, salt intrusion or agricultural runoff that may get into the water supply. Approximately one-sixth of U.S. households now get their drinking water from private wells. A compilation of state-by-state telephone and Web-based resources of local experts is included in the technical report.