Angelo Tsakopolous (plaintiff) owned Borden Ranch, an 8,400-acre ranch including wetlands, in California. Tsakopolous sought to convert the ranch into vineyards and orchards, which required deep root systems. To allow for these deep root systems, Tsakopolous engaged in deep ripping, a process in which a restrictive layer of soil is torn up and disgorged by four-to-seven-foot long metal prongs dragged behind a tractor or bulldozer. The U.S. Army Corps of Engineers (the Corps) and the Environmental Protection Agency (EPA) (defendants) sought to place limits on the deep ripping by issuing a cease-and-desist order, entering into an Administrative Order on Consent with Tsakopolous, issuing a regulatory-guidance letter, and finally issuing an Administrative Order to Tsakopolous. The Corps and the EPA’s legal basis for taking action was the Clean Water Act, 33 U.S.C. § 1311(a), which prohibits the “discharge of pollutants” into the nation’s waters. Tsakopolous responded by filing suit challenging the authority of the Corps and the EPA to regulate deep ripping. Tsakopolous argued deep ripping did not constitute the discharge of a pollutant and, in any case, fell under the Clean Water Act’s exception for normal farming. The United States filed a counterclaim for injunctive relief and civil penalties. The district court found for the United States, and Tsakopolous appealed.