The Clean Water Act limits the discharge of pollutants into “navigable waters,” which is defined by Congress as “the waters of the United States.” The EPA issued a Rule to define that term. While most agency rules are properly challenged in the federal district courts, the Act required challenges to rules issuing “any effluent limitation” or “issuing or denying any permit” to be filed in the federal courts of appeal. The Court, in a unanimous opinion by Justice Sotomayor, held that the definitional rule did not implicate the Act’s stated exceptions, and therefore the challenges must be made in the federal district courts. First, the Court reasoned that the Rule by its terms did not restrict the discharge of pollutants since it only defined a statutory term, and thus was not an “effluent limitation”. Second, the Court held that the same Rule by its terms did not approve or deny any permits. In both cases, the Court adopted a straightforward textual reading of the Rule, and rejected the Government’s argument that the potential implications of the Rule should control. A link to the opinion in Nat. Assoc. of Manufacturers v. Dept. of Defense is here.