Beginning August 4, 2025, Arizona will implement new protection for groundwater, its primary source of drinking water. The Arizona Department of Environmental Quality (ADEQ) approved modifications to the Aquifer Water Quality Standards (AWQS) and a new implementing rule. The rule will impose specific limits on groundwater pollutants that directly affect approximately 80 percent of Arizonans.

The AWQS changes impose new or updated limits on seven contaminants: Arsenic, Bromate, Chlorite, Haloacetic Acids, Microbiological Contaminants, Total Trihalomethanes, and Uranium.

With some exceptions, the new AWQS rule requires facilities in possession of an individual APP permit to begin baseline monitoring for the seven contaminants by November 4, 2025. Examples of APP permit facilities include wastewater treatment plants, landfills, and industrial operations. Once the monitoring period concludes, the facilities affected must submit a permit amendment application to ADEQ by the determined ADEQ Permit Amendment Schedule. The permittee should have received an email notice (June 4, 2025) and a physical mailer (June 9, 2025) advising the specific permit amendment due date.

These requirements are based on maximum contaminant levels set by the U.S. Environmental Protection Agency (EPA) under the Safe Drinking Water Act. According to ADEQ Water Quality Division Director, Trevor Baggiore, the AWQS changes and implementing rules represent a positive advancement for the state of Arizona.

Barbara U. Rodriguez-Pashkowski
bpashkowski@gustlaw.com
602.257.7494