Final Letter to Public Water Systems on 1,2,3-TCP Rule Adoption

January 2, 2018

The California State Water Resources Control Board has issued the final letter to public water systems outlining the 1,2,3-Trichloropropane (1,2,3-TCP)Rule adoption.  The rule includes Community Water Systems (CWS) and Non transient/Non community Water Systems (NTNC) in California.

The letter is to alert (CWS) and (NTNC) of the new regulation adopted by the State Water Resources Control Board’s Division of Drinking Water (DDW) establishing a maximum contaminant level (MCL) for 1,2,3-TCP.  These regulations were filed with the Secretary of State and became effective on December 14, 2017, with initial sampling requirements starting in the first quarter 2018.

In July 2017, the California State Water Resources Control Board adopted a new regulation prohibiting water providers from serving drinking water that contains 5 parts per trillion (ppt) or more of the man-made chemical 1,2,3-TCP.  A water provider is deemed to be out of compliance with the MCL if its running annual average of four quarterly tests equals or exceeds 5 ppt. A provider with a single test above 20 ppt will be deemed immediately out of compliance. The Board also adopted a detection limit for reporting of 5 ppt and declared granular activated carbon to be the best available technology to remove TCP from water.

Water providers should begin exploring how they can best address their TCP contamination. Will they need to remove wells from service, drill new wells, install treatment facilities, and/or purchase alternative sources of water?  Will they be able to blend water sources to achieve compliance? Addressing these questions will help water providers determine and plan for the cost of compliance. Engaging in litigation with SL Environmental Law Group to recover TCP treatment costs is but one of several steps water providers can take to address TCP contamination. Water providers will need to explore other financing options, such as grants, bonds, and rate increases to cover the costs to TCP treatment.

Final Letter to PWS_123TCP_122917