In issuing NPDES permits for discharges that will affect waters of the Reservation, the United States Environmental Protection Agency (EPA) shall utilize this chapter in order to protect waters of the Reservation. Tribal certification for the issuance of discharge permits pursuant to Sections 401, 402 and 404 of the CWA (33 U.S.C. §§ 1341 and 1342) shall be incorporated into the NPDES control document. Tribal certification shall be achieved prior to the EPA decision approving any discharge or issuing any permit for a discharge that:
A. 
Will enter ONRW designated waters of the Reservation; or
B. 
May affect OMRW designated waters of the Reservation.
The issuance of a tribal water permit will indicate the Tribe's approval. Criteria found in this chapter shall provide the basis for development of effluent limitations for NPDES permits if it is mutually agreed upon by the Tribe and EPA that a such permit should be issued. The development of effluent limitations shall take into account the interactive effects of other discharges, and components and breakdown products of the same discharge, to the same water body so that numeric criteria and other requirements contained in this chapter are met at all times, except where natural and/or background conditions cause an exceedence of the criteria.