Ariz. Rev. Stat. § 15-424
C. At the first general election held for a newly formed district, three members shall be elected. The candidate receiving the highest number of votes shall be elected to a four-year term, and the candidates having the second and third highest number of votes shall be elected to two-year terms. A district increasing its governing board to five members shall elect at the next general election members in the following manner:
D. A member who is serving on a governing board for a district that reduces the number of its governing board members to three pursuant to section 15-425.01 shall continue to serve as a member of the governing board until expiration of the member's current term of office. A district that reduces the number of its governing board members to three pursuant to section 15-425.01 shall reduce the number of its members as follows:
1. If two of the previous five offices are expiring at the first general election held after the general election in which a district reduces the number of its governing board members to three pursuant to section 15-425.01: