Oregon Revised Statutes Public Health and Safety § 450.665

(1) A petition for formation shall be signed by not less than 100 electors registered in the territory subject to the petition and shall state the number of members to be on the board of directors of the proposed authority.

(2) In its order creating the water authority, the county board shall prescribe the method of election of the board of the proposed authority from among the methods described in ORS 450.655. If the county board determines that the directors of the water authority shall be elected from zones, the county board shall establish and describe the zones, using streets and other generally recognizable features.