Standard for TCP Adopted by Water Resources Control Board
Proposed Regulation in Final Review by State Office of Administrative Law
Cal Water’s Visalia District has already begun construction of treatment facilities to meet the new maximum contaminant level (MCL) for TCP, which was adopted yesterday by the State Water Resources Control Board (State Board) and is being submitted to the Office of Administrative Law (OAL) for final review and filing with the Secretary of State. Once finalized by the OAL, the MCL of 5 parts per trillion (ppt) will become effective Oct. 1, 2017, with compliance monitoring required quarterly beginning in January 2018.
Ahead of the MCL being finalized, Cal Water has actively monitored its groundwater supplies, researched treatment options, begun design for treatment in anticipation of an eventual regulation, and secured contractors to construct and install treatment at its impacted well sites, according to Cal Water District Manager Tammy Kelly.
Cal Water is preparing to install granular-activated carbon (GAC) treatment at 11 affected sites in its Visalia District to remove TCP from the water. GAC had been identified as the most effective – and cost-effective – method to remove the constituent. Those wells impacted by TCP above the MCL that are not treated with GAC will be taken out of service while Cal Water evaluates whether to install treatment or replace them with new wells.
“Protecting our customers’ health and safety is our highest priority, and we wanted to be as prepared as possible to meet the new MCL once it was set by the public health experts,” Kelly said. “We are committed to continue meeting all water quality standards, and are working quickly to complete installation of the treatment facilities at all of our impacted sites.”
Cal Water is currently a plaintiff in litigation against the manufacturers of the TCP-containing soil fumigants. Cal Water is seeking to recover the costs associated with addressing TCP contamination in order to avoid impacting customer rates.