Central Arizona Project has more than 80 customers which fall into three groups: municipal and industrial, agricultural, and Indian users. The municipal and industrial customers include cities and water utilities which are responsible for treating drinking water and delivering it directly to residential homes, commercial buildings, and industries. CAP's agricultural subcontractors are primarily irrigation districts. CAP also delivers water to Indian communities but, by law, is not permitted to contract directly with them. Tribal nations contract for CAP water with the federal government.

Each fall customers are required to project the total amount of water they expect to use during each month in the coming year. CAP uses this information to create an annual forecast of total water deliveries. CAP offers customers such flexibility that even daily requests for changes in water deliveries are regularly accommodated. CAP's state-of-the-art computer and communications system provides CAP with the ability to provide reliable, consistent, and responsive service to its customers.