Triennial Review Rulemaking

Arizona surface water

Triennial Review Rulemaking

The Clean Water Act requires that Arizona establish surface water quality standards and review them every three years. This review process is known as the triennial review. ADEQ has a duty to conduct the triennial review of surface water quality standards, and, as appropriate, adopt or modify the standards through a rulemaking process.1

Water Quality Standards

Water quality standards are one of the cornerstones of the Clean Water Act and play a central role in the successful implementation of Arizona’s water quality management programs. Water quality standards:

  • Define water quality goals for surface waters in Arizona
  • Designate uses to be protected in Arizona’s surface waters
  • Prescribe criteria that ADEQ determines necessary to maintain and protect water quality for the designated uses
  • Provide the measure by which ADEQ assesses the water quality status of Arizona’s rivers, streams and lakes
  • Provide the regulatory basis for establishing load allocations in total maximum daily load (TMDL) analyses
  • Provide the regulatory basis for establishing water quality-based discharge limitations and controls in National Pollutant Discharge Elimination System (NPDES) permits when the Environmental Protection Agency's (EPA’s) technology-based effluent limitations are insufficient to protect water quality
  • Provide the regulatory basis for the implementation of best management practices (BMPs) to control nonpoint sources of pollution and for measuring the effectiveness of the BMPs


ADEQ is currently undergoing a triennial review of its water quality standards and potentially modifying some of the rules in Title 18, Chapter 11, Article 1. As a part of this process, ADEQ will continue to engage stakeholders at large to gather input on possible key changes to the standards and rules, and also welcomes any suggestions, questions and comments outside of any formal or informal meetings.

ADEQ has also requested three workgroups assist in providing advice regarding Triennial Review issues:

  • Antidegradation and Effluent Dependent Waters Workgroup
  • Surface Waters and Designated Uses (Appendix B) Workgroup
  • Outstanding Arizona Waters Workgroup

ADEQ expects the workgroups to provide their recommendations by the end of January 2017. ADEQ will then review the rules and standards in light of the workgroup advice, additional stakeholder input, and internal expertise.


Recorded meetings and other stakeholder engagement materials are available for download | View > 

ADEQ posts proposed rule changes online and notifies interested stakeholders throughout the process | View Water Quality Division's Draft and Proposed Rules page >

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For questions and comments, please email the Triennial Review Team | Email >