A revision of rules in the Arizona Administrative Code (A.A.C.) Title 18, Chapter 11 (R18-11) Article 1 requires EPA approval to become effective. Sometimes there is a delay in implementing these rules until they are in effect. Below is a status of federal program rules currently in effect, in rulemaking, or under review by EPA.
Rules Currently in Effect
- 2016 Surface Water Quality Standards NFRM with Update Notes | View >
Outstanding Actions in R18-11 Article 1 for the 2019 Rulemaking Combined with the Triennial Review
Narrative standards
- R18-11-120 Enforcement of Non-Permitted Discharges (A-D)
Numeric
- Appendix A Table 1
- Ammonia — A&Wc Acute, A&Wc Chronic, A&Ww Acute, A&Ww Chronic, A&Wedw Acute, A&Wedw Chronic
- Cadmium — A&Wc Acute, A&Wc Chronic, A&Ww Acute, A&Ww Chronic, A&Wedw Acute, A&Wedw Chronic, A&We Acute
- Appendix A Table 2 — Hardness 20, 100, & 400. Calculation Formula
- Acute Water Quality Standards for Dissolved Cadmium — A&Wc
- Acute Water Quality Standards for Dissolved Cadmium — A&Ww & EDW
- Acute Water Quality Standards for Dissolved Cadmium — A&We
- Appendix A Table 3 — Hardness 20, 100, & 400. Calculation Formula
- Chronic Water Quality Standards for Dissolved Cadmium — A&Ww, A&Wc, & EDW
- Appendix A Table 5
- Dissolved Copper — A&Wc Acute, A&Wc Chronic, A&Ww Acute, A&Ww Chronic, A&Wedw Acute, A&Wedw Chronic, A&We Acute
- Appendix A Table 6
- Dissolved Lead — A&Wc Chronic, A&Ww Chronic, A&Wedw Chronic
- Appendix A Table 11 — All new values based on pH and temperature
- Acute Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife cold water, Unionid Mussels Present— A&We
- Acute Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife cold water, Unionid Mussels Present— A&Ww, A&Wc, & EDW
- Appendix A Table 12 — All new values based on pH and temperature
- Acute Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife warmwater, Unionid Mussels Present — A&We
- Appendix A Table 13 — All new values based on pH and temperature
- Chronic Criteria for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife cold water and warmwater, Unionid Mussels Present
- Appendix A Table 14 — All new values based on pH and temperature
- Acute Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife warmwater, Unionid Mussels Absent
- Appendix A Table 15 — All new values based on pH and temperature
- Acute Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife warmwater, Unionid Mussels Absent
- Appendix A Table 16 — All new values based on pH and temperature
- Chronic Standards for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife warmwater, Unionid Mussels Absent
- Appendix A Table 17 — All new values based on pH and temperature
- Chronic Criteria for Total Ammonia (in mg/L, as N) for Aquatic and Wildlife cold water, Unionid Mussels Absent
During review of the 2019 rulemaking, EPA signaled to ADEQ that a number of individual pollutant parameters developed by ADEQ and listed in R18-11, Article 1, Appendix A, Table 1, for certain designated uses would be disapproved as they did not meet the requirements of the CWA. ADEQ submitted a request to formally withdraw the portions of the 2019 Triennial Review regarding proposed numeric standards for human health and safety on Dec. 21, 2021 | View >
EPA reviewed and approved portions of the 2019 rulemaking on Jan. 25, 2022. Approved changes include Arizona Administrative Code Title 18, Chapter 11: 101. Definitions, 107.01. Antidegradation Criteria, 114. Mixing Zones, and 122. Variances | View >
EPA reviewed and approved portions of the 2019 rulemaking on Oct. 26, 2022. Approved changes include Arizona Administrative Code Title 18, Chapter 11: Appendix A Numeric Water Quality Standards (carbaryl, demeton, diazinon and nonylphenol) | View >
Later in the EPA review of the 2019 rulemaking, it was communicated to ADEQ that some of the descriptions of waters in Appendix B were incorrect. ADEQ rescinded these revisions in letters to the EPA on Sept. 14, 2022, and June 2, 2023 | View >
EPA reviewed and approved portions of the 2019 rulemaking on June 10, 2025. Approved changes include Arizona Administrative Code Title 18, Chapter 11: 109 Numeric Water Quality Standards (E.coli), Appendix A Numeric Water Quality Standards (Acrolein), and Appendix B Surface Waters and Designated Uses | View >
2022 Federal Portion of Surface Water Protection Program Rulemaking
In 2022, ADEQ completed rulemaking to implement a state Surface Water Protection Program (SWPP) | View >
While much of that rulemaking was focused on the state program (R18-11 Article 2), there were some changes needed in the federal program to ensure there was no duplication between the programs. The changes were mainly limited to the removal of isolated lakes and ponds, terminal basins, and waters associated with terminal basins from R18-11 Article 1, Appendix B. ADEQ submitted the federal program changes for EPA review on Aug. 26, 2024, with final EPA review and comment pending.
2023 CWA Triennial Review & State Rulemaking
ADEQ completed the 2023 Triennial Review required by the CWA 40 CFR § 131.20 | View >
Active State Rulemaking
ADEQ is currently conducting rulemaking to address the rescinded issues identified in the 2019 Triennial Review. Formal documents associated with the rulemaking can be accessed on the Active Rulemaking Page | View >
Additional Stakeholder Materials
A revision of rules in A.A.C Title 18, Chapter 11, Article 2 is related to Arizona’s SWPP and does not require EPA approval. These rules go into effect at the completion of rulemaking.
No revisions to R18-11 Article 2 are in process at this time.
There are no other actions impacting Arizona surface water regulation in process at this time.