Arizona recognizes three types of water: surface water, groundwater, and effluent. The Arizona Department of Water Resources (ADWR) regulates the surface water sources. The surface water sources include: Colorado River water, in-state streams such as the Salt River, Verde River, Gila River, and Little Colorado River. Groundwater is actively regulated by ADWR in regulatory areas termed Active Management Areas. In these areas, ADWR enforces restrictions on groundwater appropriation and use, requires 100-year water supply planning and permitting, and enforces conservation requirements. The Arizona Department of Environmental Quality (ADEQ) regulates effluent. Effluent appropriate is governed by contractual arrangements between the owner of the effluent and the user.

The ADWR estimates Arizona uses approximately 8.0 million acre-feet (AF) annually. Arizona uses approximately 3.7 million AF of surface water annually. Colorado River uses account for 2.8 million AF of annual water use each year. The CAP delivers approximately 1.5 million AF of Colorado River to its customers annually. Non-CAP Colorado River users in Arizona use 1.3 million AF each year.

Other surface water uses include approximately 600,000 AF of Salt River and Verde River water, and approximately 200,000 AF of Gila River uses. Other surface water uses account for approximately 100,000 AF of surface water use. Groundwater makes up the majority of the remaining 4.3 million AF of use. Groundwater is used for irrigation, municipal and domestic uses. Effluent makes a very small portion of water use in Arizona. The common uses of effluent in Arizona are for cooling electric generating stations, landscape and turf irrigation, and artificial recharge.