ORS § 547.245
At any time after the expiration of five years from the confirmation of the report of the commissioners, as provided by ORS 547.235, and upon the filing of a petition with the county clerk signed by at least one-tenth of the owners of the lands within the drainage district or the owners of at least one-tenth of the lands within such district, setting forth that the original assessments or benefits are inequitable and unjust, the county court shall appoint three commissioners, as provided by ORS 547.215, to reassess the benefits in the district. The commissioners shall report the reassessment to the court. Upon the filing of the report of the commissioners, the county clerk shall give notice of hearing thereon by publication once a week for three consecutive weeks in some newspaper published in each county in the district, the last insertion to be made at least 15 days prior to the hearing. At least 10 days before the day set for hearing, exceptions may be filed by any interested person, and upon hearing the same the court shall approve the report or direct how it shall be modified and, when so modified or approved, shall confirm it. The assessment as confirmed shall take the place of all prior assessments; provided, that in no case shall the total amount of assessments be less than the outstanding obligations. The county clerk shall transmit a certified copy of the court's judgment and copy of the commissioners' report, as confirmed or amended by the court, to the secretary of the board of supervisors of the district and to the county clerk of each county having lands in the district.
ORS 547.245