Arizona's Integrated 305(b) Assessment and 303(d) Listing Report describes the status of surface water in Arizona in relation to state water quality standards. The report contains a 303(d) list of Arizona's impaired surface waters requiring the development of a Total Maximum Daily Load (TMDL) and fulfills requirements of the federal Clean Water Act sections 305(b) (assessments), 303(d) (impaired water identification), and 314 (status of lake water quality).

NOTE: This report does not provide information about the quality of water being provided by Arizona's public drinking water systems. See Safe Drinking Water for more information.

The Draft 2010 Status of Water Quality in Arizona 305(b) Assessment and 303(d) Listing Report has been revised based upon stakeholder comments received during the 30-day public comment period and has been broken down into sections for easier viewing and downloading.

• Chapter I & II: Introduction and Purpose, Water Quality Assessments by Watershed
• Water Quality Assessments by Watershed
  • Bill Williams Watershed
  • Colorado - Grand Canyon Watershed
  • Colorado - Lower Gila Watershed
  • Little Colorado Watershed
  • Middle Gila Watershed
  • Salt River Watershed
  • San Pedro Watershed
  • Santa Cruz Watershed
  • Upper Gila Watershed
  • Verde River Watershed
• Chapter III & IV: Summary Information and Action Plan
• Appendices
  • Appendix A - Assessment Units
  • Appendix B - Assessments Units by Categories
  • Appendix C - ADEQ TMDL Priority Ranking and Schedule
  • Appendix D - Critical Conditions
  • Appendix E - Delisting Impairments
  • Appendix F - Water Quality Improvements
  • Appendix G - Bioassessment Results for Perennial, Wadeable Streams
  • Appendix H - Bottom Deposits Assessment
  • Appendix I - Groundwater Assessment

Impaired Waters Lists

• 2010 Impaired Waters List waters that have been determined to be impaired and require TMDL development.
• 2006/2008 303(d) Impaired Waters List - Current U.S. EPA approved list.

The public comment period which ended April 02, 2012, was the first step in the approval process for the 2010 Status of Water Quality in Arizona 305(b) Assessment and 303(d) Listing Report. A summary of responses to comments and the 303(d) List were published in the Arizona Administrative Register (A.A.R.) for a 45-day Public Notice on June 22, 2012. ADEQ submitted the draft 2010 303(d) list of impaired waters to the U.S. EPA on October 17, 2012. The U.S. EPA partially approved and partially disapproved ADEQ's 2010 303(d) list on March 1, 2013. All interested persons wishing to submit comments on the U.S. EPA's action to add waters to Arizona’s 2010 list of impaired waters may do so in writing on or before April 8, 2013.

For more information, please contact Jason Sutter - (602) 771-4468.