Revised on: Sept. 6, 2023 -  10:30 a.m.

Water quality standards play a central role in the successful implementation of Arizona’s surface water quality management programs as required by federal Clean Water Act (CWA) and Arizona’s Surface Water Protection Program (SWPP) as described in the Arizona Administrative Code Title 18, Chapter 11 | Learn More > 

Water quality standards:

• Define water quality goals for surface waters in Arizona
• Designate uses to be protected in Arizona’s surface waters
• Prescribe criteria to maintain and protect surface water quality for the designated uses
• Provide the measure by which to assesses the water quality of Arizona’s rivers, streams and lakes
• Provide the regulatory basis for establishing load allocations in total maximum daily load (TMDL) analyzes | Learn More >
• Provide the regulatory basis for establishing water quality-based discharge permits on point sources | Learn More >
• Inform efforts to mitigate or eliminate non-point source pollution and measure effectiveness | Learn More >

The CWA requires states and Tribal Nations to review and revise, as necessary, criteria of surface water quality standards.1 This process involves a public hearing at least once every three years related to the review and revision of water quality standards and is commonly referred to as the Triennial Review. If revision of a surface water quality standard is needed, a rulemaking is conducted to update the standards in the Arizona Administrative Code Title 18, Chapter 11 | Learn More >

ADEQ will propose revisions and hold public hearings through the rulemaking process, as needed. As a result, the concept of Triennial Review will likely be more often than once every three years. The content of each rulemaking is topic-focused and scope-limited. However, in the associated public hearings, ADEQ will accept input on any aspect of the rules in the Arizona Administrative Code Title 18, Chapter 11, Article 1 and meet the requirement for a CWA Triennial Review. Public comment provided during the hearing will be considered and may be incorporated into current or future rulemakings when relevant.

Arizona also has a state SWPP. As needed, ADEQ will update the rules for SWPP listed in the Arizona Administrative Code Title 18, Chapter 11, Article 2. These updates will also be conducted through rulemaking | Learn More >

Surface Water Quality Rulemaking Status | View >

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