2015 ORS § 552.143¹
Proceedings to test validity of order or act of district board

(1) In addition to the proceeding a district is authorized to bring under ORS 33.710 (Definitions) and 33.720 (Proceeding in rem), any landowner or elector of a district may bring a like proceeding in the circuit court of the county where the lands within the district, or the greater portion thereof, are situated, to determine the validity of any order or the performance of any act mentioned in ORS 33.710 (Definitions), for which a contest is by that section provided. In such a proceeding the district board shall be made parties defendant.

(2) Service of summons shall be made on the members of the board personally if within the county where the district, or any part thereof, is situated. As to any directors not within the county, service may be had by publication of summons for a like time, and in like manner, as is provided by ORS 33.720 (Proceeding in rem). Jurisdiction shall be complete within 10 days after the date of completing publication of notice.

(3) The proceeding shall be tried and determined in the same manner as proceedings brought by the district. [1969 c.606 §9]