On March 20, 2013, the Supreme Court ruled in Decker v. Northwest Environmental Defense Center 586 U.S. (2013) reversing a ruling from the U.S. Court of Appeals for the Ninth Circuit that would have required Clean Water Act permits (CWA) for stormwater running off logging roads. The decision turns largely on deference to EPA’s interpretation of its own regulations. Whether this holding will be extended to mining or oil and gas activities depends upon the factual circumstances of the activities and the scope of existing regulations.

The Decker court was asked to consider whether forest roads associated with logging activities are “industrial facilities” for the purposes of storm water regulation under the Act. The CWA requires a discharge permit for discharges of stormwater from sites associated with industrial activity, including immediate access roads, and the question presented to the Court was whether the discharges from logging roads fit within EPA’s definition of “stormwater discharges associated with industrial activities” at 40 C.F.R. 122.26(b)(14).

EPA argued that its definition with respect to timber activities was limited to “traditional industrial sources such as sawmills” and was not intended to extend more generally to timber harvesting or to associated logging roads. The Court concluded that EPA’s interpretation was permissible, and accordingly deferred to EPA.

The Court also pointed out that one reason why EPA’s interpretation of its own regulations should be granted deference is that the State of Oregon has made extensive efforts to develop a comprehensive set of best practices to manage storm water runoff from logging roads. Whether the same argument can be made for roads in oil and gas extraction fields raises a question of fact that requires a case by case analysis.