Recently, the State Water Resources Control Board (SWRCB) Division of Drinking Water (DDW) posted updated occurrence data (dated collected between January 2014 and May 2020) for hexavalent chromium (CrVI). The 1-page summary document (hex_chrome_occurrence_data_2020_v4 (1)) presents a table with the number of sources that would be impacted by different potential CrVI Maximum Contaminant Levels (MCLs).
In 2014 DDW (at that time the Department of Public Health) adopted an MCL for CrVI of 10 µg/L. In May 2017 the Superior Court of Sacramento County invalidated the CrVI MCL indicating that DDW had “failed to properly consider the economic feasibility of complying with the MCL.” Under California’s Safe Drinking Water Act, MCLs are to be set as close to the Public Health Goal as “technologically and economically feasible, placing primary emphasis on the protection of public health.”
Following the Court’s 2017 decision, here is a quote from the SWRCB’s website: “While the Board staff disagrees with the court’s conclusion, the Board staff’s recommendation is to not appeal the trial court’s decision. It will likely be more expedient to begin the process of adopting a new MCL, rather than expending time and resources appealing the court’s order. The State Water Board hopes that the wealth of data obtained during the nearly three years the MCL has been in place will enable the Board to adopt the new regulation more quickly.”
DDW is currently working to establish criteria to determine economic feasibility and at the same time move forward with adopting a new MCL for CrVI.