The Environmental Protection Agency and Army Corps of Engineers recently announced the official repeal of an Obama administration definition of which streams, wetlands, rivers, and lakes are under the jurisdiction of the federal government for purposes of the Clean Water Act. Under the Act, “polluters” must obtain permits for discharge of substances into “navigable waters.” Implementation of the law requires a definition of “pollution” and “navigable waters.” Congress provided a definition and examples of pollution but was less helpful about “navigable waters,” defining them simply as “waters of the United States.”

Ever since the enactment of the Clean Water Act in 1972, the lack of definitional clarity in the statute and ambiguity about what constitutes a “water of the United States” has resulted in a legal struggle over the limits of federal authority to regulate pollution discharges into water. Jonathan Adler’s article in the Summer issue of Regulation summarizes the convoluted history of the struggle over the regulatory definition of “waters of the United States” and provides a framework for evaluating the proper role of states and the federal government in water pollution control.

Many environmentalists believe that broad assertions of federal regulatory authority increase environmental benefits and less federal authority results in environmental degradation. The New York Times, for example, said that the repeal of the Obama administration rule “has implications far beyond the pollution that will now be allowed to flow freely into waterways.”

In contrast, Adler argues the federal government should focus its efforts on situations in which “pollution crosses state lines and the affected states are unable to resolve the conflict on their own.” Thus, he is concerned that the proposed Trump administration replacement for the repealed rule does “not specifically identify interstate waters as ‘waters of the United States.’”

Environmentalists’ second reason for advocating extensive federal regulation of water pollution is their belief that states will cater to polluters, allowing intrastate water and wetland degradation in return for jobs, income, and development. Adler argues that the evidence on state environmental regulation does not support this belief. For example, “the history of state wetland regulation … paints quite a different picture. Not only did states not wait for the federal government to begin regulating wetlands, but … many states have adopted programs that reach beyond federal requirements.”

So, in Adler’s view, while the Trump administration’s proposed replacement falls short because it neglects a legitimate role for the federal government in regulating interstate waterways, placing limits on the federal role in water pollution policy will not lead to the degradation that environmentalists foresee.