ORS § 545.393
When an irrigation district has entered into a contract with the United States providing for payment to the United States under any federal reclamation law, the board of directors of the irrigation district, at any regular meeting that is not later than its meeting on the second Tuesday of September of any year, may enter a resolution fixing the date upon which computation shall be made of the necessary funds to be raised as provided in ORS 545.391 and the date when the board shall convene as a board of equalization. In the resolution, the board of directors may authorize the discounts that may be provided for in the contract between the district and the United States for payment of assessments in full on or before December 31 of the year in which the assessments are made. The board of directors shall make the levy of assessments in such amount that the discount can be allowed without reducing collections below the required amount. The resolution shall be published for two consecutive weeks in a newspaper in the county in which the office of the district is located. The resolution thereafter shall remain in full force and effect until revoked by the board. If the district does not collect its own assessments, the assessment shall be completed and the levy filed with the county assessor prior to November 30 of the year in which the assessment is made. After receipt of a certified copy of the resolution, the county officers charged with the collection of irrigation district assessments shall collect the assessments in accord with the provisions of the resolution.
ORS 545.393