On January 8, 2013, the U.S. Supreme Court issued a unanimous decision in Los Angeles County Flood Control District v. NRDC, Inc., a closely watched case under the federal Clean Water Act (CWA) relating to pollutants from municipal storm water systems. Prior to the decision, there was speculation that the U.S. Supreme Court may use the case to address issues relating to the scope and jurisdiction of the CWA, but ultimately the Court issued a very narrow decision holding that the flow of water with pollutants from an improved portion of a navigable waterway into an unimproved portion of the same waterway does not qualify as a “discharge of a pollutant” under the CWA.
The case involved a citizen suit under § 505 of the CWA by two environmental organizations against the Los Angeles County Flood Control District alleging that, based upon in stream monitoring stations showing exceedances of water quality standards, the District was violating the terms of its permit for the operation of a municipal separate storm sewer system (MS4)—a drainage system that collects, transports, and discharges storm water. However, relying on its prior decision in South Fla. Water Management Dist. v. Miccosukee Tribe, 541 U.S. 95 (2004), the Supreme Court held that the flow of polluted storm water out of a concrete-lined portion of the waterway controlled by the District into an unimproved portion of the same waterway did not constitute the “addition” of a pollutant into a navigable water sufficient to qualify as the “discharge” of a pollutant under the CWA.