Amid the ongoing public health pandemic, EPA has issued two fact sheets suggesting it may conclude that a federal drinking water standard for perchlorate is not warranted. In a June 2019 blog post we reported that EPA asked the public whether it should set a Maximum Contaminant Level (MCL) for perchlorate. Setting an MCL for this substance could affect both public water systems and other regulated entities. But EPA’s preliminary move last week appears to suggest that EPA is preparing to conclude that an MCL may not be warranted for perchlorate.
On May 14, 2020, EPA issued two factsheets indicating that levels of perchlorate in drinking water are declining. The first fact sheet, “Reductions of Perchlorate in Drinking Water,” analyzed the updated data used to develop the June 2019 notice, compared to data from 2001-2005 which served as a basis for EPA’s 2011 determination to regulate perchlorate. In its fact sheet, EPA largely attributes perchlorate reductions to the promulgation of chemical-specific drinking water regulations in California and Massachusetts and groundwater remediation efforts in Nevada. Other activities that have contributed to reducing perchlorate levels include cleanup of large point source contamination and remediation at Superfund sites throughout the country. The factsheet also provides updates regarding the fifteen water systems identified as having elevated perchlorate levels in 2001-2005.
EPA also released a second factsheet titled “Steps Water Systems Can Take to Address Perchlorate in Drinking Water”. This document provides step-by-step advice to water systems that may be concerned with the levels of perchlorate in their drinking water. The factsheet provides guidance to water systems on how to test water, interpret the results, compare them to state drinking water standards and guidelines, and communicate them to customers, as well as how to reduce perchlorate levels by treatment and non-treatment methods and by changes in storage and handling of common disinfectants solutions.
EPA is expected to issue a final decision regarding regulation of perchlorate in June 2020.