WASHINGTON — Since the establishment of the federal Safe Drinking Water Act (SDWA) more than 35 years ago, the safety of the U.S. drinking water supply has been an ongoing priority for health officials. Operating under the authority of the SDWA, the Environmental Protection Agency (EPA) sets drinking water standards to control contaminants in the public drinking water supply. To date, the EPA has identified nearly 90 separate contaminants whose concentrations in drinking water are regulated under its National Primary Drinking Water Regulations.

The fact that contaminants are detected in trace amounts in drinking water does not alone imply risk to humans. Significant research is needed to understand both the scope of the problem and its implications for the public drinking water supply. To determine whether a contaminant should be regulated, the EPA analyzes peer reviewed science addressing a number of variables, including the occurrence levels of a contaminant in the environment, routes of human exposure and the potential health effects of exposure.

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The EPA also collects data under its Unregulated Contaminant Monitoring program on contaminants that are suspected to be present in drinking water but that are not currently regulated. In support of that data collection effort, the EPA has recently implemented its third Unregulated Contaminant Monitoring Rule (UCMR 3), which will require public water systems (PWSs) to conduct assessment monitoring for the presence of 28 additional chemicals and two viruses during a 12-month period beginning in January 2013. The EPA will use the data from this and prior UCMR assessment phases to determine whether further drinking water regulations are in the interest of public health.

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This UL white paper provides a detailed overview of the EPA’s UCMR 3 monitoring program for PWSs. Beginning with background information on the EPA’s role in the regulation of drinking water contaminants, the paper then offers specific details on the UCMR 3 monitoring program requirements, including the specific substances subject to monitoring, sampling and testing methods, and important program schedules and deadlines. The white paper concludes with considerations for PWSs regarding compliance with UCMR 3 monitoring requirements and recommendations on the selection of a testing laboratory to conduct UCMR sample testing.

Read the entire white paper here.