Natural Resources Defense Council, Inc. v. U.S. EPA

Under the Clean Water Act, the discharge of any pollutant into navigable waters was unlawful except as allowed under the National Pollution Discharge Elimination System permit program. The Clean Water Act prescribed limitations on specific effluents based on the available pollution-control technology. These limitations were supplemented as needed to protect water quality in specific bodies of water. The Clean Water Act was structured to implement increasingly rigorous technology-based standards over time. The standards were enforced by requiring all dischargers to obtain a permit that set out limitations for specific effluents. In its final regulations issued in 1984, the United States Environmental Protection Agency (EPA) (defendant) permanently prohibited bypasses, i.e., the diversion of waste streams from a treatment facility, subject to two exceptions: within effluent limits for essential maintenance, or in excess of effluent limitations only in an emergency. An industry group, Natural Resources Defense Council, Inc. (the council) (plaintiff) challenged the prohibition as unauthorized under the Clean Water Act and inconsistent with the act’s policies. The council argued that (1) the prohibition acted as a de facto effluent limitation imposed without the necessary cost-benefit analysis, and (2) the prohibition was contrary to the legislative policy statement to encourage experimentation rather than dictate specific treatment processes.