EPA Seeks Comment on Proposed MCL for Perchlorate in Public Drinking Water Systems

On May 23, 2019 the EPA released a pre-publication notice of proposed rulemaking that seeks public input on a range of options regarding the regulation of perchlorate in public drinking water systems. The agency is seeking comment on a proposed National Primary Drinking Water Regulation (NPDWR) for perchlorate to establish a Maximum Contaminant Level (MCL) and a health-based Maximum Contaminant Level Goal (MCLG) at 56 micrograms per liter. 

In addition, the agency is seeking comment on three alternative regulatory options:

• An MCL and MCLG for perchlorate set at 18 micrograms per liter.
• An MCL and MCLG for perchlorate set at 90 micrograms per liter.
• Withdrawal of the agency’s 2011 determination to regulate perchlorate in drinking water.

Some states have already established MCLs:

• Massachusetts: 2 ppb (2 micrograms per liter)
• California: 6 ppb (6 micrograms per liter)

To read more about the EPA's proposal and how to submit comments, click here.