Oregon Revised Statutes Cities § 224.310

(1) “Municipality” means a duly incorporated city or town having a population of not more than 3,500 inhabitants as determined from the latest official enumeration of inhabitants, either federal or state, made prior to the date of authorization of the construction and establishment by the municipality of a sewerage system or of an extension to an existing sewerage system.

(2) “Sewerage system” means complete or primary sewage treatment and disposal facilities, sewer mains, pumping stations, and all equipment and appurtenances necessary, useful or convenient for the treatment or disposal of sewage, or any portion of such a system, whether within or without the corporate limits of a municipality.