Groundwater quality of individual wells and small systems in Arizona

Approximately half of the waterborne disease outbreaks documented annually in the United States are caused by contaminated groundwater. In 2006, the US Environmental Protection Agency promulgated the final Ground Water Rule to reduce the risk of exposure to fecal contamination that may be present in community and noncommunity public groundwater systems. In most states, private drinking water systems are not regulated by local health and environmental agencies. The goal of the study presented in this article was to assess the microbial, physical, and chemical quality of groundwater in individual wells and small public water systems in Arizona, and it was the first such study in an arid region of the United States. Of the well sites sampled, 43% of the systems were positive for total coliforms, 16% for fecal coliforms, and 4% for Escherichia coli. In addition, 95% of systems exceeded at least one primary and/or secondary drinking water standard, suggesting that better guidance is needed to ensure the water quality of these systems.-NLP.