(1) “District” means a sanitary district duly organized under the provisions of ORS 450.005 to 450.245, having an assessed valuation of not more than $250,000.
(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 boundaries of a district.