Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 547.079

(1) Whenever the engineer or secretary of a drainage district notifies the supervisors that any flood control project is less efficient, by reason of the failure of the owner of the premises upon which it is situated to prevent obstructions, repair, clean or grade the same, the board of supervisors shall serve or cause to be served upon such owner, if the owner is known and residing within the county in which the district is situate, or if not a resident of the county, then upon the occupant of the premises, a notice in writing notifying the owner or occupant of the clogged or obstructed condition of the flood control project.

(2) The notice shall be served by delivering to the owner, occupant or person in charge of the premises a copy thereof certified to be such by the person serving it, or if there is no occupant or the owner is not a resident of the county, then the notice shall be served by posting a copy of it in a conspicuous place upon the premises. Immediately after serving or posting the notice, the person serving it, by authority of the board of supervisors, shall file the original notice with the county clerk of the county in which service is made, together with a return on the notice stating the time and manner of making service. The notice and return, when so filed, shall be retained as a public record of the county.