Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 553.760

No tract of land shall be considered to be benefited by the construction, operation, maintenance or improvement of irrigation works unless the owner of such land enters into an irrigation contract with the district. The irrigation contract shall be in such form as shall be prescribed by the district. Upon being executed the contract shall be recorded with the county clerk of the county in which such lands are located and the recording of the contract shall constitute notice that such lands are subject to all maintenance and operation assessments thereafter levied and all other assessments thereafter or theretofore levied by the district.