The Colorado River is an important source of water for much of the western United States, including Arizona. The Central Arizona Project (CAP) carries 1.5 million acre-feet of water from the Colorado River to Pima, Pinal, and Maricopa counties each year. Tucson Water distributed 93,250 acre-feet to over 220,000 customers in 2012.
The below image compares 1999 water levels to 2013 water level. Click here to learn more about how this drop in water levels caused a cutback in water flowing down river into Lake Mead and Lake Havasu.