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California Court Approves Flexible Approach to Regulating Storm Water Discharges Under Clean Water Act


A recent decision from the California Court of Appeal holds that local permitting authorities have wide discretion to regulate storm water discharges under the Clean Water Act ("CWA"). Rejecting an environmental group’s challenge that federal regulations mandated numeric effluent limits on storm water discharges into the San Diego Bay, the court found Congress intended a flexible approach to implementing the CWA that includes alternative effluent control strategies. This is good news for regulators, builders and developers who are seeking innovative approaches to storm water runoff.

In Divers’ Environmental Conservation Organization v. State Water Resources Control Board, et al. (Nov. 29, 2006) 2006 LEXIS 1874, an environmental group challenged the NPDES discharge permit issued by the California Regional Water Quality Board, San Diego Region ("Regional Board") to the U.S. Department of the Navy, et al. ("Navy") regulating discharges from a Naval Base into the San Diego Bay.

The NPDES permit at issue required the Navy implement a "Storm Water Pollution Prevention Plan" employing "Best Management Practices" ("BMPs") to minimize pollutant discharges into the bay from industrial activities at the base. This included evaluating potential sources of pollution impacting storm water discharges and implementing site specific BMPs to reduce or prevent pollutants in the discharges. The permit also mandated the Navy to consider non-structural BMPs (e.g., preventative maintenance and spill response procedures) to reduce offsite flow of pollutants. If these measures failed, the Navy was to consider structural BMPs (e.g., retention ponds and treatment facilities).

In addition to the prevention plan, the Regional Board conducted a study of water quality of the storm water discharges. Based on the study, the Regional Board included in the permit a numeric limit on the toxicity in the Navy’s total effluent and set "benchmarks" for copper and zinc, two constituents of concern. If these benchmarks were exceeded, the Navy was required to improve its BMPs accordingly. Moreover, the Navy was obligated to review its BMPs annually to ensure they are preventing pollutant discharges. If the Regional Board found the prevention plan to be deficient in meeting permit requirements, the permit required the plan be revised to implement additional BMPs.

Divers’ Environmental Conservation Organization challenged the permit on the grounds the CWA and accompanying regulations required the Regional Board to (1) analyze whether the particular pollutants in the Navy’s storm water discharges had the "reasonable potential" to cause or contribute to a violation of any state water quality standard, and then (2) set numeric "water quality based effluent limitations" (WQBELs) on the discharges.

Rejecting the petitioner’s demands, the appellate court observed the EPA has expressed its preference for a flexible approach to regulating storm water discharges through BMPs, instead of imposing technology-based or water quality based numeric effluent limitations. Thus, while a numeric analysis of particular pollutants in storm water discharges would in most instances be the most effective means of meeting regulatory requirements, a Regional Board could reasonably conclude in other instances that a detailed numeric analysis is not a cost effective means of performing the required "reasonable potential" analysis.

Similarly, the court rejected the petitioner’s second argument that the Regional Board was only authorized to employ BMPs in the permit if numeric WQBELs were not feasible. Finding nothing in the CWA that limited the permitting agency’s use of BMPs in controlling storm water discharges, the court found that the EPA, along with the Regional Board, could reasonably conclude that by enacting section 402(p) of the CWA in 1987, Congress intended to permit the EPA and permitting authorities "wide discretion in regulating storm water runoff, including the use of BMPs where the agencies believed they were appropriate."

To view the court's decision, click here.

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