November 26, 2019, Judge William Young ruled that discharges to groundwater are not subject to Clean Water Act jurisdiction, even if they ultimately reach surface waters that are unambiguously waters of the United States. He did not wade into the murky waters, as it were, of the Maui case or any of the various judicial theories for or against jurisdiction. Instead, he took a simpler path.

As Judge Young noted, all of the various Circuit Court decisions on this issue were rendered before EPA issued its Interpretive Statement concluding that the CWA does not regulate discharges to groundwater. He then upheld the Interpretive Statement on the basis of Chevron deference.

I think that Judge Young got it right. It’s difficult for anyone to argue with a straight face that the CWA is unambiguous. Thus, the only question is whether EPA’s interpretation is reasonable under the statute. It’s important to remember that the question is not whether EPA is right; the question is whether its interpretation of the statute is reasonable. From my viewpoint, EPA’s position is bad policy, but it’s not an unreasonable interpretation of the statute.