Tucson, Arizona, located in the southwestern United States, is an area known for its natural beauty (Figures 1, 2 and 3). Like much of the Southwest, the region is growing rapidly. With little annual rainfall and no nearby surface water supplies, a key objective for the region is ensuring that growth is based on sustainable water supplies. This paper discusses how regulations concerning the use of groundwater and the manner in which water is supplied have influenced the region’s landscape.