Oregon Revised Statutes Public Health and Safety § 451.472

(1) A district may construct, maintain and operate only those service facilities specified by ORS 451.010 that were authorized upon formation of the district. However, additional authority regarding service facilities may be given to a district by a proceeding initiated, conducted and completed in the same manner as is provided for in the original formation of a district or as otherwise provided by law.

(2) A district may be formed, as provided in ORS 451.410 to 451.610, that contains territory that is also included in another district formed under ORS 451.410 to 451.610 if the district is formed to construct, maintain and operate service facilities that the existing district is not authorized to construct, maintain and operate.

(3) The consent of not less than 70 percent of the cities located within the boundaries of the district is required to authorize a district established to provide sewage works to also provide drainage works.