Central Arizona Project

The Central Arizona Project (CAP) is a 336-mile long system of aqueducts, tunnels, pumping plants and pipelines and is the largest single resource of renewable water supplies in the state of Arizona. The system designed to bring about 1.5 million acre-feet of Colorado River water per year to water users in Pima, Pinal and Maricopa counties. CAP carries water from Lake Havasu near Parker to the southern boundary of the San Xavier Indian Reservation southwest of Tucson.


CAP_canal_aerialThe primary purpose of the CAP is to help Arizona conserve its groundwater supplies by importing surface water from the Colorado River, whose supply is renewed yearly by rainfall and snowmelt. The water significantly reduces reliance on groundwater sources. The City’s current CAP allocation is approximately 81,281 acre-feet. This represents approximately two-thirds of the City’s total water supply at build-out.


The City began using CAP water in 1987. CAP water is treated at the 70 MGD CAP Water Treatment Plant, which is located at the Water Campus facility.

CAP website