ORS 308.151
Section 5, chapter 414, Oregon Laws 2017, provides:
Sec. 5. (1) A definition of "area" adopted under section 2 of this 2017 Act [308.151] may not be applied to any assessment year beginning before January 1, 2019.
(2) Notwithstanding subsection (1) of this section, a definition of "area" adopted under section 2 of this 2017 Act may be applied to assessment years beginning on or after January 1, 2018, with the written consent of the assessor of the county in which the city adopting the definition is located. [2017 c. 414, § 5]