The U.S. Court of Appeals for the First Circuit has overturned its bar on Clean Water Act (“CWA”) citizen suits seeking declaratory relief when a state is “diligently” prosecuting a violation.  In the opinion, the Court agreed with environmentalists and the EPA that its prior opinion was at odds with the text and congressional intent of the CWA.  In the language of the Court, “the limitations set forth in Section 309(g)(6)(A) bars only a citizen suit that seeks to apply civil penalty for an ongoing violation of the CWA and not a citizen suit for declaratory and prospective injunctive relief to address an ongoing violation.”  The ruling is expected to greatly increase the number of citizen suits filed in the First Circuit.