Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 545.535

Any assessment upon land shall be a lien against the property assessed. The lien for all payments due under any contract with the United States or the State of Oregon or for the payment of principal or interest of bonds deposited with the United States or the State of Oregon shall be a preferred lien to any assessments for bonds issued subsequent to the date of the contract or the issuance of the bonds deposited with the United States or the State of Oregon. A district assessment lien shall not be removed until the assessments are paid with interest and penalties or the property sold for the payment of the assessments, together with interest and penalties.