A.R.S. § 42-15105
"For property that is valued by the assessor, in the case of new construction, additions to, deletions from or splits or consolidations of assessment parcels and changes in property use that occur after September 30 of the preceding year and before October 1 of the valuation year:
1. The assessor shall notify the owner of the property of any change in the valuation on or before September 30 of the valuation year.
2. Within twenty-five days after the date of the assessor's notice, the property owner may appeal the valuation to the state board of equalization if the property is located in a county with a population of five hundred thousand persons or more or to the county board of equalization if the property is located in any other county."
NOTE: ALL NOTICES OF CHANGE WHICH ARE ISSUED ON SEPTEMBER 30, ARE TO BE VALUED AS IF THE NEW CONSTRUCTION EXISTED ON THE VALUATION DATE OF JANUARY 1 OF THE SAME YEAR. THE FULL CASH VALUE SHOULD REFLECT WHAT THE VALUE WOULD HAVE BEEN, IF THE CONSTRUCTION WAS IN EXISTENCE ON JANUARY 1 AND HAD BEEN VALUED WITH THE MARKET INFORMATION AVAILABLE AT THAT TIME. SALES INFORMATION AFTER THE VALUATION DATE CAN BE USED, BUT SHOULD BE ADJUSTED FOR TIME. ONLY CONSTRUCTION COMPLETE AS OF SEPTEMBER 30 SHOULD BE CONSIDERED.