EPA Releases UCMR4 Reference Concentrations

On May 15th, EPA posted the UCMR4 Reference Concentrations on its website. Reference Concentrations can function as a point of comparison for UCMR4 monitoring results, keeping in mind that the primary purpose of unregulated contaminant monitoring is to inform the regulatory development process, by providing robust national occurrence data for a contaminant that might be under consideration for a potential federal regulation.

ASDWA members and staff worked with EPA’s Technical Services Center (TSC) to emphasize the primary purposed of the UCMR4 monitoring and further emphasizing that the Reference Concentrations aren’t legally enforceable standards. UCMR4 monitoring started in January 2018 and will continue through December 2020. EPA is planning for the first public release of UCMR4 data sometime in the fall (comparable timeframe to UCMR3).