Ariz. Rev. Stat. § 48-2702
The board of directors shall, on or before the first meeting of the board of supervisors in July each year, furnish the board of supervisors and the county assessor of the county in which the district is located, or if the district is not entirely within a county, then as otherwise provided by this article, to the board of supervisors and county assessors of each county in which any portion of the district is located, a written estimate of the amount of money needed for the purposes of the district for the ensuing fiscal year. The amount shall be sufficient to pay the annual interest on the outstanding bonds, the estimated cost of repairs, the incidental expenses of the district, and, in any year in which any bonds fall due, the principal of the outstanding bonds as they mature.
A.R.S. § 48-2702