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Contact EPA Pacific Southwest

Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Arizona Animal Waste Management

Arizona's 130,000 dairy cows, which produced 302 million gallons of milk in 1998, also make dairies a significant source of animal waste. In addition to dairies, Arizona also has cattle, hog, and poultry feeding operations.


In the 1990s, Arizona's dairies declined in number but grew in size, increasing milk production over 44% between 1993 and 1998. During the same five year period (1993-1998), the average number of cows per dairy increased from 290 to 500. These numbers reflect the recent concentration of Arizona dairies and their waste.

Geographic Concentration

Arizona's AFOs and CAFOs are also concentrated geographically. Seventy to ninety percent of Arizona's (CAFOs) are in Maricopa, Pinal and Yuma Counties. According to the 1997 Census of Agriculture, Maricopa County ranked seventh in the nation in number of milk cows per county.

EPA and the Arizona Department of Environmental Quality Exiting EPA (disclaimer) (ADEQ) are working together to prevent pollution from dairies and other types of AFOs. In addition to conducting periodic workshops on compliance with National Pollutant Discharge Elimination System (NPDES) permits, including the use of best management practices for animal waste management, EPA and ADEQ also work to reduce animal waste pollution through inspections and other compliance actions. Also, the AZ Department of Agriculture and USDA NRCS are assisting producers with the development of nutrient management plans.

Permitting Requirements

Because of recent court challenges affecting the NPDES program applicable to AZ, please contact the EPA regarding questions on how to obtain NPDES coverage for CAFOs in AZ.

Arizona's Agricultural General Permits

ADEQ also uses its own authority under state laws to regulate AFOs. Arizona's Agricultural General Permits require AFOs to retain wastewater/stormwater on site, with exceptions for the largest 25-year, 24-hour storm events, and follow best management practices when applying fertilizer. ADEQ also requires AFOs to meet State and Federal Water Quality Standards. See the ADEQ Quality Water Pollution Control Web site for more information.

State Links

The following links may also provide helpful information about state, county and local efforts to manage animal waste effectively:

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