Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 545.385

(1) Notwithstanding ORS 545.381 or 545.482 to 545.508, an irrigation district that assesses land in the district under ORS 545.381 or 545.482 to 545.508 may assess any land within the district to which the district furnishes or supplies water for irrigation purposes and which:

(2) The amount of the assessment on land described in subsection (1) of this section shall be an amount that the board determines to be just, taking into consideration the benefit to the land assessed and extra expenses, if any, of the landowner or holder in using such water. However, the amount may not exceed the amount assessed against irrigable acres lying below the level of the canals or ditches of the district.

(3) Notwithstanding ORS 545.381 or 545.482 to 545.508, an irrigation district which assesses land in the district under ORS 545.381 or 545.482 to 545.508 may assess a service charge, in addition to the regular assessment, against subdivided and small tract lands that have appurtenant water rights and to which irrigation water is furnished or is available for delivery. A service charge authorized by this section shall be assessed against lands only when delivery of water to these lands requires operation, construction and maintenance costs substantially greater than operation, construction and maintenance costs involved in delivering water to the majority of other lands in the district. All such small tract or subdivided lands shall be placed in groupings rounded up to the next whole acre, and each grouping shall be assessed as a single class.