We again consider this case on remand from the Supreme Court's decision in Gwaltney of Smithfield, Ltd. v. Chesapeake Bay Foundation, Inc., --- U.S. ----, 108 S.Ct. 376, 98 L.Ed.2d 306 (1987). In Gwaltney, the Supreme Court held that Sec. 505(a) of the Clean Water Act, 33 U.S.C. Sec. 1365(a), does not confer federal jurisdiction over citizen suits for wholly past violations, but does permit such suits when there is a pattern of intermittent violations, even if there is no violation at the moment suit is filed. Upon due consideration of the supplemental memoranda filed by the parties, we remand to the district court for further findings on whether citizen-plaintiffs have proved an ongoing violation within the meaning of the Supreme Court's decision. We do not think that the decisional process would be aided by further oral argument.

The Supreme Court's decision in Gwaltney resolved a conflict in the Circuit Courts of Appeals, see 108 S.Ct. at 380-81, by vacating our judgment in Chesapeake Bay Foundation, Inc. v. Gwaltney of Smithfield, Ltd., 791 F.2d 304, 308 n. 9 (4 Cir.1986) (holding that Sec. 505 applies to a citizen-plaintiff claim of wholly past violations). The Supreme Court held that citizen-plaintiff suits under Sec. 505 could not be based on wholly past violations, but carefully distinguished an allegation of a wholly past violation from allegations of intermittent or sporadic violations. The Court noted legislative history in support of the proposition that

an intermittent polluter--one who violates permit limitations one month of every three--is just as much "in violation" of the Act as a continuous violator.

108 S.Ct. at 384.

The Supreme Court remanded in light of its holding that "Sec. 505 confers jurisdiction over citizen suits when citizen-plaintiffs make a good faith allegation of continuous or intermittent violation...." 108 S.Ct. at 385. As the Supreme Court observed (id.), we perceived "a very sound argument" that plaintiff's allegations of continuing violations were made in good faith, but expressly declined to rule on the district court's finding of a sufficient good faith allegation. 791 F.2d at 308 n. 9. We must now review the district court's finding that citizen-plaintiffs made a good faith allegation of ongoing violation sufficient to maintain jurisdiction.

We also think that we are confronted with an additional issue on remand. Consistent with the language of the majority opinion, we must also review the district court's decision for a determination of whether citizen-plaintiffs have proved their allegation of continuous or intermittent violations, as required in order to prevail. See 108 S.Ct. at 386.^[1]

The district court did find a good faith allegation of ongoing violation sufficient to avoid threshhold jurisdictional challenges. We now hold that the district court's finding that the allegations were made in good faith, see 611 F.Supp. 1542, 1549 n. 8, is not clearly erroneous.

We remand to the district court for further findings as to whether, on the merits, plaintiffs proved at trial an ongoing violation. Citizen-plaintiffs may accomplish this either (1) by proving violations that continue on or after the date the complaint is filed, or (2) by adducing evidence from which a reasonable trier of fact could find a continuing likelihood of a recurrence in intermittent or sporadic violations. Intermittent or sporadic violations do not cease to be ongoing until the date when there is no real likelihood of repetition. While the district court did make subsidiary findings pertinent to this issue, see, e.g., 611 F.Supp. at 1549 n. 8, 1566 (Appendix A), it did not make a direct finding as to whether citizen-plaintiffs proved the existence of intermittent or sporadic violations constituting an ongoing violation.

Consistent with the guidance of the Supreme Court majority and concurring opinions, the district court may wish to consider whether remedial actions were taken to cure violations, the ex ante probability that such remedial measures would be effective, and any other evidence presented during the proceedings that bears on whether the risk of defendant's continued violation had been completely eradicated when citizen-plaintiffs filed suit.

REMANDED.