In Camarillo Sanitary District v. State Water Resources Control Board (2025) 113 Cal.App.5th 407, the Fifth District Court of Appeal held that the State Water Resources Control Board’s (SWRCB’s) new effluent toxicity testing provisions complied with state law, including CEQA, but violated the federal Clean Water Act (CWA).

Background

Following dissatisfaction with existing whole effluent toxicity testing, the SWRCB adopted new toxicity provisions based on the EPA’s Test of Significant Toxicity, aiming to improve precision, reduce false positives or negatives, and encourage a higher quality and quantity of test data. The new provisions applied both to the waters of the United States and the surface waters of the state. As a result, entities regulated under the National Pollutant Discharge Elimination System (NPDES) were now required to obtain permits subject to the requirements of the provisions.

A group of entities subject to the new toxicity provisions challenged the provisions and the Test of Significant Toxicity, claiming the Test of Significant Toxicity was not an approved method under federal law, that the toxicity provisions were not legally authorized, and that SWRCB violated CEQA in adopting them. The trial court denied the writ. The plaintiffs appealed.

Court of Appeal’s Decision

New Test Not Allowed Under Clean Water Act

Whole effluent toxicity testing seeks to determine the overall toxicity of water by taking a broader approach in testing water pollutants and measuring the overall toxicity of a discharge based on its effect on biological organisms. Even when all individual pollutant limits are met, the tested water may still be toxic based on a combination of pollutants or because it contains substances not yet found to be toxic. The CWA’s approved tests provide two “statistical endpoints” to measure if water is toxic: (1) the no observed effect concentration—which measures the highest concentration with no harmful effects; and (2) the 25 percent inhibition concentration—which identifies the concentration that causes a 25 percent reduction in organism growth or reproduction. However, SWRCB’s new Test of Significant Toxicity labeled water as toxic if test organisms showed 75 percent or less survival, growth, or reproduction compared to a control sample.

The Fifth District held the Test of Significant Toxicity cannot be utilized in NPDES permitting to measure whole effluent toxicity because it is inconsistent with the CWA and fundamentally changed what qualified as toxic water. According to the court, this new definition of toxicity was inconsistent with outcomes from the existing CWA tests. As NPDES permitting is governed by the CWA, which sets a regulatory “floor” for water pollution standards, the court determined this was improper.

State Water Law and Administrative Procedure Act Claims

While the court determined that the new Test of Significant Toxicity could not be used for NPDES permitting, it also reviewed the Toxicity Provisions’ adoption as a state water policy and held that it was compliant with state law, including the Porter-Cologne Water Quality Control Act and the California Administrative Procedure Act.

SWRCB Satisfied CEQA

Appellants argued that SWRCB incorrectly utilized a substitute CEQA document under its certified regulatory program instead of preparing an EIR. The court disagreed. Under Public Resources Code section 21080.5, subdivision (a), when a certified regulatory program requires documentation containing environmental information, that documentation may be used in place of an EIR, provided the program has been certified by the Secretary of the Natural Resources Agency. The program at issue was the “Water Quality Control (Basin)/208 Planning Program of the State Board and the Regional Water Quality Control Boards,” which was adopted and certified to support the ongoing development and updating of Regional Water Quality Control Plans to reflect evolving state policies aimed at protecting water quality.

Appellants’ argument hinged on the inclusion of “basin” within the program’s title, contending that the program only applied to basin planning rather than broader water quality control actions. Rejecting this interpretation, the court found the language was broad enough to cover the entire state water quality control planning process.

Appellants also argued the environmental document failed to adequately consider and mitigate potentially significant impacts of the Toxicity Provisions’ adoption. The court again disagreed, holding that SWRCB satisfied the requirements of CEQA. Since the regulations did not specify the actual compliance methods that permittees were required to use, the analysis was of a “general, programmatic nature.” Although no quantitative analysis was conducted regarding the implementation of specific toxicity controls as that approach was deemed too speculative by SWRCB, it concluded that the major category of reasonably foreseeable methods of compliance would be “an increase in monitoring, testing, and laboratory analysis.”

Additionally, though SWRCB found the choices of future toxicity controls to be speculative and not reasonably foreseeable, it still discussed the potential impacts of possible toxicity controls and provided an environmental checklist in its analysis. SWRCB ultimately concluded that compliance with the toxicity provisions was projected to have a potentially significant impact on agricultural and forestry resources. These conclusions were followed by a detailed discussion of the provisions’ expected impacts and related mitigation.

The court found that this analysis sufficiently discussed the degree of uncertainty, reasonably foreseeable alternatives, significant foreseeable environmental effects, and the effects of mitigation efforts. A more detailed disclosure of impacts and mitigation efforts was not required since the exact parameters of generally foreseeable future actions could not reasonably be predicted. Further, even if the court found SWRCB’s conclusion improper, the environmental checklist met the disclosure requirements for generally foreseeable impacts that cannot be accurately predicted.

– Sara Helms