RESTON, VA — A new study by the US Geological Survey (USGS) has found that more than 20 percent of private domestic water wells sampled nationwide contain at least one contaminant at levels of potential health concern, the USGS stated in a March 27 news release.

USGS scientists sampled about 2,100 private wells in 48 states from 1991 to 2004 in 30 of the nation’s principal aquifers used for water supply. They found that the contaminants most frequently measured at concentrations of potential health concern were inorganic contaminants, including naturally occurring radon and arsenic, according to the news release.

Nitrate was the most common inorganic contaminant derived from man-made sources, such as from fertilizer applications and septic tanks. It was found at concentrations greater than the federal drinking water standard for public water supplies of 10 parts per million (ppm). Nitrate was greater than the standard in about 4 percent of sampled wells.

Complete findings are available online.

About 43 million people, or 15 percent of the nation’s population, use drinking water from private wells, which are not regulated by the federal Safe Drinking Water Act. The quality of water drawn from private wells is also not regulated by most states.

USGS Associate Director for Water Matt Larsen is quoted in the news release as saying, “The results of this study are important because they show that a large number of people may be unknowingly affected. Greater attention to the quality of drinking water from private wells and continued public education are important steps toward the goal of protecting public health.”

The study shows that the occurrence of selected contaminants varies across the country, often following distinct geographic patterns related to geology, geochemical conditions, and land use.

During a March 27 Congressional briefing sponsored by the USGS National Water Quality Assessment Program and the Water Environment Federation (WEF), the Water Quality Association (WQA) offered members of Congress information about methods to help ensure safe well water, the WQA announced in March 27 press release.

WQA provided members of Congress with a copy of its online fact sheet regarding contaminants in drinking water. WQA represents the point-of-use/point-of-entry water treatment industry.

WQA said it has joined a task force to develop independent testing standards that will be able to tell consumers what devices are successful at removing many of these newly discovered contaminants.

To read the full news release, click here.

For related information, click here.