By Philip L. Comella and Craig B. Simonsen

The Supreme Court held today in Los Angeles County Flood Control Dist. v. Natural Resources Defense Council, Inc., No. 11-460 (January 8, 2013), that the flow of water 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 Clean Water Act. In doing so, the Supreme Court decision reaffirmed its prior decision in South Florida Water Management District v. Miccosukee Tribe of Indians, 541 U.S. 95 (2004), that the transfer of polluted water between two parts of the same water body does not constitute a discharge of pollutants under the Clean Water Act.

The Supreme Court’s ruling reversed a decision by the Ninth Circuit Court of Appeals, NRDC v. County of Los Angeles, 636 F.3d 1235 (9th Cir. 2011), which had held that the water control district had violated its discharge permit by channeling polluted stormwater from improved to unimproved portions of the receiving water bodies.