As discussed in prior blog posts, the Federal Circuits became split (Part 1) in 2018 on whether the Clean Water Act (“CWA” or the “Act”) regulates discharges of pollutants from point sources that reach navigable waters through nonpoint sources, such as groundwater. Recently, the U.S. Supreme Court granted certiorari in one of those Circuit decisions (Part 2), and the case is still in front of the Supreme Court. While U.S. EPA had requested comments on this and other issues (Part 3), the agency’s current position was unknown until recently. On April 15, 2019, EPA released an interpretive statement and corresponding press release providing new guidance on whether the CWA permitting requirements apply to discharges directly to groundwater (78 Fed. Reg. 16810 (April 23, 2019)).

The Agency’s Interpretative Statement

In a fact sheet about the recent statement, EPA stated that “releases of pollutants to groundwater are categorically excluded from the Act’s permitting requirements.” EPA notes in its interpretative statement that it is a fundamental principle of hydrology that many groundwaters and surface waters are linked through the hydrologic cycle. However, EPA then builds a case that the text, structure, and legislative history of the Act demonstrate Congress’s intent to leave the regulation of groundwater wholly to the states. EPA notes that the operative, enforceable provisions of the Act that make up the National Pollutant Discharge Elimination System (NPDES) permitting program neither reference nor contemplate releases to groundwater, and that the legislative history of the Act supports Congress’s intent to deliberately exclude groundwater.

EPA also distinguishes and explains its prior statements on this topic. Of particular note, EPA has previously made statements indicating that discharges to groundwater with a direct hydrologic connection to surface water are subject to CWA NPDES requirements. EPA indicates that many of these statements were made in situations where the complex jurisdictional issues of releasing pollutants to groundwater were not the central focus or where the rule or permit was never finalized. EPA believes that when these prior statements were made, EPA had failed to take into account Congress’s unique treatment of groundwater in the CWA. EPA also explicitly notes that it has consistently maintained the position that groundwater is not a “water of the United States” and that groundwater is not a point source.

Lastly, EPA discusses court decisions, policy considerations, and other federal statutes. Consistent with the Trump Administration’s reliance on state rights, EPA indicates that it is up to states to regulate groundwater quality in the manner best suited to their particular circumstances. EPA also notes that several other federal statutes, specifically the Safe Drinking Water Act, Resource Conservation and Recovery Act (RCRA), and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), contain provisions aimed at protecting groundwater quality and, which unlike the CWA, provide a clear federal role for regulating groundwater.


EPA has stated that the interpretative statement is effective immediately in all states except states within the Fourth and Ninth Circuits due to the pending U.S. Supreme Court case. In those states where it is now effective, the interpretative statement adds clarity to the CWA NPDES permitting process for situations where point sources discharge into groundwater.
Unfortunately, there is no way of knowing how this interpretation will affect the U.S. Supreme Court’s ruling, or how the Court’s ruling will affect this interpretation. Until the U.S. Supreme Court rules on this issue, there will continue to be some uncertainty regarding whether discharges to groundwater which are hydrologically connected to surface waters require NPDES permits under the CWA.

Contact Us

For more information about EPA’s Interpretive Statement or the CWA, please contact Phillip R. Bower or Daniel A. Fanning of Husch Blackwell’s Environmental team.