EPA Issues Final Action for Perchlorate in Drinking Water

U.S. Environmental Protection Agency (EPA) issued a final action regarding the regulation of perchlorate under the Safe Drinking Water Act (SDWA). Considering the best available science and the proactive steps that EPA, states and public water systems have taken to reduce perchlorate levels, the agency has determined that perchlorate does not meet the criteria for regulation as a drinking water contaminant under the SDWA. Therefore, the agency is withdrawing the 2011 regulatory determination and is making a final determination to not issue a national regulation for perchlorate at this time.

“Today’s decision is built on science and local success stories and fulfills President Trump’s promise to pare back burdensome ‘one-size-fits-all’ overregulation for the American people,” said EPA Administrator Andrew Wheeler. “State and local water systems are effectively and efficiently managing levels of perchlorate. Our state partners deserve credit for their leadership on protecting public health in their communities, not unnecessary federal intervention.”

Reductions of perchlorate contamination have resulted from actions taken by EPA, states and public water systems. The main factors contributing to the decrease in perchlorate levels include:

• Drinking water regulations for perchlorate in Massachusetts and California.
• Federal and state remediation activities at perchlorate contaminated sites, particularly the ongoing remediation efforts in the state of Nevada to address perchlorate contamination in groundwater adjacent to the lower Colorado River upstream of Lake Mead.
• Improved procedures for storage and handling of hypochlorite solutions used as drinking water disinfectants.

EPA also performed a new health impact analysis based on recommendations from the Science Advisory Board. The new analysis shows that the concentrations at which perchlorate may present a public health concern are higher than the concentrations considered in the 2011 regulatory determination.

The updated occurrence information and the new health impact analysis are the best available information. Based on this updated data and analysis, EPA is making a final determination that perchlorate is not found in drinking water with a frequency and at levels of public health concern to support a meaningful opportunity for health risk reduction through a national perchlorate drinking water regulation.

EPA will continue to work with state partners to provide safe drinking water to all Americans. To assist states and drinking water systems interested in reducing perchlorate concentrations, EPA is providing steps that water systems can take to mitigate the contaminant if and where it occurs.