Oregon Revised Statutes Water Resources: Irrigation, Drainage, Flood Control, Reclamation § 540.100

(1) When water users are unable to agree to the distribution or division of water, a majority of them may request the watermaster of the district in which the distribution or division is in dispute to make a just division or distribution of water among the parties entitled to the use of the water. The request shall be in writing and shall set forth the pertinent facts of the dispute.

(2) If no provision has been made for payment of the necessary assistant watermaster or expenses as provided by ORS 540.080, the assistant shall be paid by the water users among whom the distribution or division is made.

(3) The expense of any assistant watermaster shall be paid by the water users in proportion to the area of land for which each water user is entitled to the use of water, so that each one shall pay the same rate per acre.