Phoenix is a desert but it wasn't ever devoid of water like people think. Its more like a "green desert" of sorts. Its very existence is the result of the sheer amount of water naturally running through the area. Was once the alfalfla capital of the US due to the water and the number of growing seasons.

The only reason it started growing so quickly is because A/C became available. Prior to that they couldn't use swamp coolers mid summer due to the monsoon season making it too humid to work. Water, power, etc, all of that was already there.

A better example is someplace like Las Vegas.