California Code, Government Code - GOV § 24002.5

(a) A person may not exercise the powers and duties of the office of assessor unless he or she holds a valid appraiser's certificate issued by the State Board of Equalization pursuant to Article 8 (commencing with Section 670) of Chapter 3 of Part 2 of Division 1 of the Revenue and Taxation Code.

(b) Notwithstanding subdivision (a), a duly elected or appointed person may exercise the powers and duties of assessor, for a period not to exceed one year, if he or she acquires a temporary appraiser's certificate from the State Board of Equalization no later than 30 days after taking office.

(c) This section does not apply to any person holding the office of assessor on January 1, 1997.