Private Wells--Public Health Risks
For communities using private or unregulated drinking water wells, groundwater vulnerability to microbial contamination poses a significant public health risk. Historically, a significant number of drinking-water-associated waterborne illness outbreaks and contamination events have been attributed to unregulated water systems (Craun & Calderon, 2003; DeSimone, Hamilton, & Gilliom, 2009; Yoder et al., 2008). Although many environmental health programs are required to inspect and test private wells only at the time of permitting (when a new well is constructed or repaired), illnesses and problems associated with these systems constitute a major part of water safety initiatives pursued by these programs.
In the wake of government austerity measures, many environmental health permitting programs will curtail services associated with private wells. In its efforts to support local environmental health programs, the Centers for Disease Control and Prevention's Environmental Health Specialists Network (EHS-Net) Water Program has developed a groundwater vulnerability assessment tool, Land-use Hydrology and Topography (LHT), piloted in 18 counties in the state of Georgia to assess the effectiveness of this approach for identifying unregulated wells for prioritized intervention (Baloch & Sahar, 2011). This column presents a case for using a groundwater vulnerability mapping approach to prioritize intervention programs for those private or individual wells most vulnerable to contamination.
Groundwater Vulnerability Assessment Approach
The U.S. Environmental Protection Agency (U.S. EPA) defines a public water system (PWS) as a water system serving a minimum of 15 connections or 25 persons for at least 60 days in a year (U.S. EPA, 2003, 2004). Unlike unregulated or private wells, wells supplying water to PWSs are protected by state wellhead programs (WHPs). These programs provide a localized approach to protection by focusing on the critical surface and subsurface areas surrounding a well connected to the PWS known as wellhead protection areas (WHPAs). This exact approach is not a viable option for unregulated or private wells because identifying and delineating WHPAs for every private well in a jurisdiction is not practical given the large number and sparse locations of these systems. Furthermore, budget cuts across government agencies necessitate sound planning and project prioritization to direct limited funds...