With primacy in place, Arizona is positioned to play a leading role in balancing groundwater protection with energy development and carbon management.
On September 10, 2025, the U.S. Environmental Protection Agency (EPA) announced a final rule granting Arizona primacy to administer all classes of underground injection wells under the Safe Drinking Water Act (SDWA). This decision transfers authority for permitting and oversight of the Underground Injection Control (UIC) program from EPA to the Arizona Department of Environmental Quality (ADEQ).
UIC Program
The UIC program safeguards underground drinking water sources by regulating six classes of wells, from hazardous waste disposal (Class I) to carbon capture and storage (Class VI). States may obtain primacy if they demonstrate their program meets federal requirements.
EPA’s approval followed a detailed technical and legal review of Arizona’s application and determined that ADEQ has the resources and statutory authority to implement the program consistent with SDWA.
Reprinted courtesy of Patrick J. Paul, Snell & Wilmer and John Habib, Snell & Wilmer
Mr. Paul may be contacted at ppaul@swlaw.com
Mr. Habib may be contacted at jhabib@swlaw.com