Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 547.620

(1) Whenever there is in the sinking fund a surplus of $500 or more, over and above the interest maturing before the next levy, the district treasurer shall give notice for two weeks in one or more newspapers of general circulation printed and published in the county in which the district was first organized. The notice shall state the amount of such surplus and that on the day and hour named in the notice, sealed propositions will be received at the office of the district treasurer for surrender of bonds of the district.

(2) The district treasurer shall, at the time and place named, open the propositions and accept the lowest bid. However, no bid shall be accepted for an amount exceeding the par value of the bonds with accrued interest thereon and seven percent premium. If bids are not offered at that figure, or less, sufficient to exhaust the amount of surplus on hand, the board of trustees may then call in any bonds of the district, giving the numbers thereof in the exact order of their issuance beginning with the lowest or first number, and redeem the same at par value and five percent premium with accrued interest to date of such recall. Thereafter interest thereon ceases and the amount due shall be set aside for payment of the bonds whenever presented.