The historical record of the cost of pumping groundwater in Arizona is examined. Measures used are the cost per acre‐foot per foot of lift, the cost per acre‐foot, the water cost per acre for important crops, and the total water cost per farm for representative general crop farms. Costs are presented in actual dollars and dollars adjusted by GNP implicit price deflators. Whereas pumping depths have been rising rapidly, costs per acre‐foot per foot of lift have been falling, adjusted costs per acre‐foot have been almost constant, and per acre costs and total farm costs relative to both total costs and total returns have fluctuated throughout the time period examined, sometimes being lower but often being higher than costs at the present time.