Only from farming things that honestly shouldn't be grown here. There's actually plenty for people to use / drink, which is a LOT lower than farming uses.
From the Arizona Department of Water:
Irrigated agriculture is the largest user of water in Arizona, consuming about 74 percent of the available water supply. In the past, this percentage was as high as 90 percent; reductions have been the result of both urbanization of agricultural lands and heavy investment by the irrigated agriculture industry in conservation measures both on-farm and in delivery systems.