Arizona Thermal Discharges regulations & environmental compliance analysis

Arizona Thermal Discharges: What you need to know

Governing Law and Regulations

Water quality standards: Arizona Administrative Code Rules (AZ Admin. Code R) 18-11-108 and AZ Admin. Code R 18-11-101 to 18-11-606

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Temperature limitations: AZ Admin. Code R 18-11-109

Regulatory Agencies

Arizona Department of Environmental Quality (ADEQ) Water Quality Division

U.S. Environmental Protection Agency (EPA) Region 9

See ADDRESSES & CONTACTS for addresses and telephone numbers.

See national section for basic information and federal regulations.

Comparison: State vs. Federal

Rules. Arizona regulates water temperatures under its general water quality standards. See the state section EFFLUENT LIMITATIONS for more information on the state water quality standards. The state has adopted the federal rules for thermal pollution variances under Section 316(a) of the Clean Water Act (CWA) and has specific water body standards for thermal discharges. See the national section THERMAL DISCHARGES for information on the federal thermal discharge limitations.

Administration and enforcement. ADEQ's Water Quality Division administers and enforces water quality standards in Arizona, including thermal discharge standards.

State Requirements


AZ Admin. Code R 18-11-109

The maximum allowable increase in ambient water temperature due to a thermal discharge is as follows:

Maximum Temperature Increase Surface Water Designated Use Designated Use Definition
1°C Aquatic and wildlife (cold water) (A&Wc) The use of a surface water by animals, plants, or other cold-water organisms, generally occurring at elevations greater than 5,000 feet, for habitation, growth, or propagation.
3°C Aquatic and wildlife (effluent-dependent water) (A&Wedw) The use of an ...

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