The Ninth Circuit held that the Environmental Protection Agency (EPA) did not have a mandatory duty to make findings when provided with information regarding violations of the Clean Water Act (CWA).[1] Furthermore, EPA does not have a mandatory enforcement duty even after a violation has been found.

The Grand Canyon chapter of the Sierra Club (the Club) sued EPA under the CWA for failure to take action against the City of Nogales and the International Boundary and Water Commission (Boundary Commission) for operating a wastewater treatment plant that was allegedly polluting the Santa Cruz River. The treatment plant is located in Arizona near the United States-Mexico border and serves nearly 200,000 people in Nogales, Arizona, and Nogales, Sonora, Mexico. At the time of suit the plant operated under an expired permit issued by EPA, and according to reports submitted by the Boundary Commission to EPA, had violated its permit limitations 128 times in the past five years.

The Club sought enforcement action from EPA under the citizen suit provision of the CWA.[2] Although the Club, Nogales and the Boundary Commission reached a settlement, the resulting consent decree was not binding on EPA. Thus the Club's claim against the agency was preserved. The CWA citizen suit provision authorizes any citizen to sue EPA "where there is alleged a failure of the Administrator to perform any act or duty . . . which is not discretionary."[3] EPA argued that its decision not to enforce was discretionary. The district court agreed and dismissed for lack of jurisdiction, and the Club appealed.

The Ninth Circuit separately addressed whether EPA had a duty to make findings and whether the agency had a duty to take enforcement action. As it did in Friends of the Cowlitz v. FERC,[4] the court cited Heckler v. Chaney[5] for the "traditional presumption" that an agency retains unreviewable prosecutorial discretion unless Congress has indicated otherwise.[6] Although this presumption of agency discretion can be overcome, the language of the CWA does not impose on EPA a mandatory duty to investigate alleged violations or to make findings. The Club based its claim on section 309(a)(3) of the CWA, which states that "[w]henever on the basis of any information available to him the Administrator finds that any person is in violation . . . he shall issue an order requiring such person to comply." [7] However, the court concluded that this section concerns the duty of the Administrator only after a finding has been made; it does not create an initial duty to investigate. Furthermore, requiring EPA to investigate every complaint could interfere with the agency's ability to investigate and enforce the most serious violations.

Likewise, regarding enforcement, the court was unwilling to intrude on EPA's expertise in ordering agency priorities. Even when EPA finds a violation, the seemingly mandatory "shall"[8] in section 309 merely authorizes rather than commands EPA to take enforcement action. "Particularly when used in a statute that prospectively affects government action, 'shall' is sometimes the equivalent of 'may.'"[9] The statutory structure of the CWA demonstrates that enforcement is at the discretion of the EPA. That is, by providing for citizen suits, Congress acknowledged that EPA would not always act. The court found further support for EPA's prosecutorial discretion in the Act's legislative history.[10]

Finding that EPA did not fail to perform any non-discretionary duty, the Ninth Circuit affirmed the district court in dismissing the Club's citizen suit for lack of subject matter jurisdiction.