Oregon Revised Statutes Public Health and Safety § 450.835

(1) Contract with any person, or enter into intergovernmental agreements under ORS chapter 190, for the use or joint operation of all or any portion of any sewage disposal or drainage system; or

(2) Purchase all or any portion of any sewage disposal or drainage system on such terms as are fair and reasonable. Where the area served by such system, or part thereof, is situated within the authority, the authority may agree, on such terms as are fair and reasonable, to furnish sewage disposal or drainage functions for the area then served by such sewage disposal or drainage system. Under this subsection, as a part of the purchase agreement and on such terms as are fair and reasonable, the authority may assume liability for any outstanding bonded or other indebtedness incurred prior to the time of purchase in connection with the facilities to be purchased.