A.R.S. § 40-334: Discrimination between persons, localities or classes of service as to rates, charges, service or facilities prohibited

A. A public service corporation shall not, as to rates, charges, service, facilities or in any other respect, make or grant any preference or advantage to any person or subject any person to any prejudice or disadvantage.

B. No public service corporation shall establish or maintain any unreasonable difference as to rates, charges, service, facilities or in any other respect, either between localities or between classes of service.

C. The commission may determine any question of fact arising under this section.