We all knew it was likely to happen, but foreshadowing does not lessen the shock to the regulatory world, nonetheless, when it does. You guessed it! The definition of waters of the U.S. as it relates to Federal Clean Water Act permitting has recently changed, yet again! On August 30, 2021, a U.S. District Judge for the District of Arizona vacated and remanded the Navigable Waters Protection Rule (NWPR) in the case of Pascua Yaqui Tribe v. U.S. Environmental Protection Agency, No. CV-20-00266-TUC-RM (D. Arizona Aug. 30, 2021). In light of this order, the U.S. EPA and USACE have halted implementation of the NWPR and are interpreting waters of the U.S. consistent with the pre-2015 Clean Water Rule until further notice. The pre-2015 Clean Water Rule era requires following the guidance developed in 2007 and 2008 for implementing the definition of waters of the U.S. following the Rapanos v. United States, and Carabell v. United States Supreme Court decisions. As you may know, this has implications for all pending Approved Jurisdictional Determinations and 404 Permits from USACE and U.S. EPA. We are already in the process of updating our clients’ Aquatic Resources Delineation Reports and permit packages. Contact us if you think your project may be impacted and/or if you have questions!