In the U.S., North Carolina has the second highest number of residents who rely on private wells for their drinking water supply. Maupin and coauthors (2014) reported that about 3.3 million North Carolina residents (35% of the population) used private wells in 2010. Percentages varied by county, with the highest county having 85.4% of the residents using private wells (Figure 1). Unlike public water systems that benefit from the regulatory safeguards of the Safe Drinking Water Act, there are no federal regulations for private wells in the U.S. Testing, treating, maintaining, and managing private wells are up to well owners, often with little to no technical or financial support.
The North Carolina General Assembly has passed statutes to protect groundwater and the health of residents who use private wells since the 1970s. Most of those statutes included construction regulations (e.g., offset distances to known sources of contamination and grouting) and well disinfection. A statute enacted in 2008 gave exclusive authority to local health departments for permitting the repair and construction of wells, conducting well inspections, and testing new wells (North Carolina General Assembly, 2006). This statute helps in learning about water quality issues of new private wells in the state.
In 2015, the Private Well and Health Program (PWHP) of the North Carolina Department of Health and Human Services received funding from the Centers for Disease Control and Prevention's (CDC) Safe Water for Community Health (Safe WATCH) Program to enhance services to private well users. PWHP was understaffed, had limited access to water quality data, and lacked established partnerships, which prevented them from enhancing services for private well users and better protecting their health.
Vulnerability of Private Wells and Water Quality
PWHP used CDC funding to hire dedicated staff to identify and address threats to water quality in private wells. Staff found that urinary arsenic levels across the U.S. declined in users of public water systems but not in users of private wells after the U.S. Environmental Protection Agency (U.S. EPA) reduced the arsenic maximum contaminant level (MCL) from 0.05 mg/L to 0.01 mg/L in 2006 (Nigra et al., 2017; Welch, Smit, Cardenas, Hystad, & Kile, 2018). This finding created awareness for assessing the data available on arsenic and other contaminants in water samples of new private wells across North Carolina.
The CDC grant helped...