Ariz. Rev. Stat. § 15-1024
B. The proceeds of the sale of the bonds shall be deposited in the county treasury to the credit of the bond building fund of the school district. Such deposits may be drawn out for the purposes authorized by this article as other school monies are drawn. If a balance remains in the bond building fund after the acquisition or construction of facilities is completed for which the bonds were issued and on written request of the governing board:
D. The amount of net premium associated with a bond issue may be used only for one or more of the following:
3. For any other purpose, if the district has voter authorization and available capacity under its debt limitations and the amount of net premium used for such purpose will reduce in an equal amount both: