Oregon Revised Statutes Protection from Fire § 478.495

(1) When a proposal for dividing a district into zones is approved by the voters of a district, a proposal for changing the boundaries of the zones shall not be submitted to the voters at the regular district election next following such approval, but may be submitted at any regular district election thereafter.

(2) Following approval of the formation of zones within a district by the voters of the district, the boundaries of the zones shall not be changed by the district board unless notice of that change is given to, and approved by, the voters of the district as provided in ORS 478.480 (2), 478.485 and 478.490.