Oregon Revised Statutes Public Health and Safety § 454.215

(1) Any municipality may own, acquire, construct, equip, operate and maintain, either within or without its statutory or corporate limits, in whole or in part, disposal systems with all appurtenances necessary, useful or convenient for the collection, treatment and disposal of sewage. The municipality may acquire by gift, grant, purchase or condemnation necessary lands and rights of way therefor, either within or without its statutory or corporate limits. For the purpose of acquiring property for such uses, the municipality may invoke and shall have the rights, powers and privileges granted to public corporations under the provisions of existing or future laws pertaining to this subject.

(2) The authority given by ORS 454.205 to 454.255 shall be in addition to, and not in derogation of any power existing in the municipality under any constitutional, statutory or charter provisions now or hereafter existing.