On Aug. 28, the U.S. Environmental Protection Agency and U.S. Army’s Clean Water Rule went into effect in 37 states. The rule is intended to clarify which waters fall under the jurisdiction of the Clean Water Act. However, a preliminary injunction by the U.S. District Court for the District of North Dakota blocked implementation of the rule in 13 states.

The fractured implementation of the final rule is expected to result in confusion. The Obama Administration publicly expressed strong disagreement with the ruling, and pointed to two other federal courts that dismissed petitions seeking similar injunctions.

Thirteen states — Alaska, Arizona, Arkansas, Colorado, Idaho, Missouri, Montana, Nebraska, Nevada, New Mexico, North Dakota, South Dakota, and Wyoming — remain subject to the prior 2008 Clean Water Act guidance.