Ariz. Rev. Stat. § 15-771
A. Each school district shall make available an educational program for preschool children with disabilities who reside in the school district and who are not already receiving services that have been provided through the department of education. A charter school may choose to make available an educational program for preschool children with disabilities. The state board of education shall prescribe rules for use by school districts in the provision of educational programs for preschool children with disabilities. School districts are required to, and charter schools may, make available educational programs for preschool children who meet the definition of one of the conditions prescribed in paragraphs 1 through 5 of this subsection. For the purposes of calculating average daily membership, school districts and charter schools may count only those preschool children who meet the definition of one of the following conditions: