Los Angeles County Flood Control District v. Natural Resources Defense Council, Inc.

Summary

The Supreme Court held that the flow of polluted water from an improved portion of a river to an unimproved portion of the same river does not constitute a "discharge of a pollutant" under the Clean Water Act. The Court reversed the Ninth Circuit's judgment, relying on its prior decision in Miccosukee which established that transferring water within the same water body is not an "addition" of pollutants. Justice Alito concurred in the judgment.