EPA proposes new rule on MS4 operations

The Environmental Protection Agency (EPA) is proposing changes to the regulations governing small municipal separate storm sewer system (MS4) permits to respond to a remand from the United States Court of Appeals for the Ninth Circuit in Environmental Defense Center, et al. v. EPA, 344 F.3d 832 (9th Cir. 2003), which ordered EPA to finalize the rule by no later than Nov. 17, 2016.

In that decision, the court determined that the regulations for providing coverage under small MS4 general permits did not provide for adequate public notice and opportunity to request a hearing. Additionally, the court found that EPA failed to require permitting authority review of the best management practices (BMPs) to be used at a particular MS4 to ensure that the small MS4 permittee reduces pollutants in the discharge from their systems to the “maximum extent practicable” (MEP), the standard established by the Clean Water Act for such permits.

EPA’s proposal would revise the small MS4 regulations to ensure that the permitting authority determines the adequacy of BMPs and other requirements and provides public notice and the opportunity to request a public hearing on the requirements for each MS4. The proposal would not establish any new substantive requirements for small MS4s.