Governing Law and Regulations
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.
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 ... |