On Tuesday, December 7, 2021, the U.S. Environmental Protection Agency and the Army Corps of Engineers published for public comment a proposed rule revising the definition of “Waters of the United States” (“WOTUS”).  The agencies indicate the proposal would “meet the objective of the Clean Water Act and ensure critical protections for the nation’s vital water resources, which support public health, environmental protection, agricultural activity, and economic growth across the United States.”

The proposed rule replaces the “interstate commerce” test with the “relatively permanent” and “significant nexus” standards.  Under the proposal, a water may be a WOTUS when it “significantly affects” (i.e., has more than speculative or insubstantial effects on) any one form of chemical, physical, or biological integrity of a downstream traditional navigable water, interstate water, or the territorial seas.  The proposal also identifies specific factors that will be considered when assessing whether the functions provided by the water are more than speculative or insubstantial. Notably, the agencies offer comparison between the “significant nexus” standard and the agencies’ approach in the proposed rule, and the “functional equivalent” standard outlined by the U.S. Supreme Court in County of Maui v. Hawaii Wildlife Fund.  The agencies suggest that these standards should be applied while keeping in mind the purposes of the Clean Water Act.

Particularly on the heavily-debated issue of groundwater, the agencies explain in a footnote:

The agencies note that they have never interpreted groundwater to be a “water of the United States” under the Clean Water Act. The proposed rule makes no change to that longstanding interpretation.  This interpretation was recently confirmed by the U.S. Supreme Court.  While groundwater itself is not a “water of the United States,” discharges of pollutants to groundwater that reach a jurisdictional surface require a NPDES permit where the discharge through groundwater is the “functional equivalent” of a direct discharge from the point source into navigable waters.”  (Internal citations omitted.)

The proposal also re-promulgates two longstanding exclusions from the definition – the exclusion for prior converted cropland, and the exclusion for waste treatment systems.  Unless extended, the public comment period for the proposed rule will end February 7, 2022.

A copy of the Federal Register notice may be viewed here. 

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