In a lengthy and highly technical published opinion filed August 5, 2025, the Fifth District Court of Appeal partly reversed and partly affirmed a judgment that had upheld the State Water Resources Control Board’s (“State Water Board” or “SWRCB”) adoption of the “State Policy for Water Quality Control: Toxicity Provisions” (the “Toxicity Provisions”), which policy in relevant part required use of a new “Test of Significant Toxicity” (“TST”) in analyzing a type of pollution known as “whole effluent toxicity.” … As to the CEQA aspects of the Court’s opinion, it provides valuable CEQA-compliance guidance to agencies with certified regulatory programs adopting new regulations that will trigger generally foreseeable future compliance actions the parameters of which are speculative.