Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 553.730

No levy of an ad valorem tax under ORS 553.710 for any one year shall exceed one-half of one percent (0.005) of the real market value of all taxable property within the subdistrict, computed in accordance with ORS 308.207. If the total sum of money required to be raised under the terms of a contract entered into by a district, together with the sum of money to be raised to pay the costs and expenses of the district incurred in connection therewith, exceeds such limitation, a levy for each year thereafter shall be made by the district until the entire contract obligation has been discharged.