That is because they are trying to make it look as green as Kansas. Perhaps watering just the greens at the country club and have the suburbs use a desert theme in their landscaping would make better use of the available resources.The water problems will only increase as the population of Phoenix and Tucson continue to grow. . The water demands of Phoenix alone are enormous.
The odds are the whole area might be getting more moisture in the winter so that should help as it would then attract a lot more people as the surrounding area does begin to look like Kansas.
Pipelines also solve little problems like that.