The Supreme Court has long struggled to define the scope of federal jurisdiction over pollution control under the Clean Water Act (CWA). During the Court’s last term, that issue returned to the forefront in County of Maui, Hawaii v. Hawaii Wildlife Fund. The case involved pollution from a wastewater treatment facility that reached the Pacific Ocean and caused coral die-offs at a nearby beach park. However, the facility did not discharge pollutants directly into the Pacific, but rather through groundwater. The Court heard the case to answer the question of whether pollution that reached federally covered waters indirectly, such as through groundwater, required CWA permits. On the way to the Supreme Court clash, an unusual relationship between a local government and an industry-aligned law firm led the county to reframe the case from a factual disagreement to a clash over the jurisdictional scope of the CWA.
The Supreme Court held that discharges that reach navigable waters after traveling through another medium require permits if they are the “functional equivalent” of a direct discharge based on a multi-factor test. This test extends far beyond the particular context of discharges through groundwater. Past disputes in both in the courts and over rulemakings in the CWA’s implementing agencies focused on the definition of the statutory term “waters of the United States” (WOTUS) to set the reach of the CWA’s federal jurisdiction. However, the Maui test shows that the real jurisdictional reach of the Act extends to discharges that eventually enter those waters. As a result, federal jurisdiction is broader than past cases indicated, not only for pollutants that travel through groundwater, but for any water pollution. This jurisdictional scope will cover not only point source pollution but also wetlands regulation. As a result, Maui will become the most important case on the federal reach over water pollution.