In a March 19 ruling in State of Texas, et al. v. EPA et al., a U.S. District Court for the Southern District of Texas granted Texas and Idaho’s Motions to block the Biden Administration’s “durable” definition of “Waters of the United States” (WOTUS). The purpose of the rule was to establish a durable definition of WOTUS grounded in the authority provided by Congress in the Clean Water Act, the best available science, and extensive implementation experience in protecting the Nation’s waters.

In questioning the viability of the rule, Judge Brown noted that the final rule’s broad application of the “significant nexus” test and its expansion of jurisdiction to all interstate waters, regardless of navigability, are two provisions on which he believes the Plaintiffs are likely to succeed on their merits.

Brown notes, for instance, that the significant nexus test set out in the rule varies significantly from the Supreme Court’s Rapanos “significant nexus test” in the level of connectivity required to navigable waters.

Brown comments in dicta that this interpretation of the Act to include all interstate waters irrespective of any limiting principle raises serious federalism questions. The EPA has signaled its intention to vigorously defend the rule against its challengers.