Oregon Revised Statutes Public Health and Safety § 450.840

(1) The cost of construction of a sewage disposal system, including treatment plants and trunk or lateral sewers, or a drainage system shall be borne by the area directly benefited by the system. The property within such area shall bear such cost in the manner provided in ORS 450.855.

(2) The cost of operation and maintenance of sewage disposal systems and drainage systems shall be borne by the area directly benefited by such systems. The property within such area shall bear such cost in the manner provided in ORS 450.880.

(3) The costs and expenses of the authority which are not chargeable under ORS 450.600 to 450.989 to any particular area within the authority such as overall planning, expenses of the board, conduct of elections and hearings and mosquito and other insect control shall be borne by the entire authority in the manner provided in ORS 450.885 (1)(a).