(1) Authority granted hereunder shall be limited to the administration of the permit program within applicant's jurisdictional boundaries as now existing or as hereafter changed.

(2) Grants of authority to municipalities hereunder shall be limited to the conduct of a permit program for the discharge of commercial and industrial wastes into a sewerage system and shall confer no authority to issue permits for the discharge of such wastes into surface or groundwaters of the state. Administration of permit requirements for waste discharges other than commercial and industrial wastes entering a sewerage system, shall remain solely with the department.

(3) No authorization made hereunder shall be construed as limiting or abridging the powers or abrogating the duties required of the department. The department may initiate appropriate enforcement action against a municipality to whom authority has been granted hereunder, or against any discharger for violations of any requirements of chapter 90.48 RCW, the FWPCAA, or regulations thereunder.