ORS § 545.291
When a parcel of land lying within an irrigation district is subdivided or partitioned into tracts, and plats of such subdivision are filed as provided by law, if the owners fail properly to apportion the water to their various tracts in the subdivision, the board of directors may employ some competent person to distribute and apportion water for the tracts. The reasonable cost of the distribution and apportionment of water shall be apportioned each year by the board to the tracts. The cost of the distribution and apportionment of water shall be assessed or charged by the board as a special charge to the tracts in the same manner as other assessments or charges are made and extended upon the tax rolls of the county in which the irrigation district lies. The assessments or charges so levied and apportioned shall be a lien upon the tracts and shall be collected in the same manner as all other assessments or charges are levied and collected by the board.
ORS 545.291