Total Maximum Daily Load (TMDL) Process & Progress

The following is an overview of the process for establishing a TMDL for pollutant parameters on an impaired water. This process, depending on complexity, watershed size, the number of pollutants contributing to the impairment, etc., typically takes three to five years.

Step 1 — Project Prioritization

Arizona’s list of TMDLs on impaired waters is prioritized every two years as part of the Clean Water Act 305(b) & 303(d) Assessment | Learn More >

Step 2 - Data Review

Compilation of supporting information and existing data

Step 3 - Sampling and Analysis Plan

Includes site selection, sampling design, frequency, project duration, methods, budget, a health and safety plan, and other relevant information

Step 4 - Data Collection

Implementation of the sampling and analysis plan

Step 5 - Data Analysis

Analysis of all available data to identify sources of pollutants and recommend implementation activities to restore the water quality

Step 6 - Draft Report

Draft TMDL report incorporating data analysis findings and conclusions

Step 7 - Public Comment

Publish notice to receive public comment on the draft report in the Arizona Administrative Register per Arizona Revised Statutes §49-234(D)

Step 8 - Finalize Report

Review and respond to public comments, incorporate input into the report, if appropriate, and publish the final report in the Arizona Administrative Register per Arizona Revised Statutes §49-234(E)

Step 9 - TMDL Final Report Approval

Submit to EPA for approval

Access Current TMDLs

Find Arizona TMDL documents using the EPA's How’s My Waterway Application | View/Download How-To > | Visit EPA Application >

Opportunities for Public Input

In addition to the required public comment period in Arizona Revised Statutes §49-234, ADEQ will accept informal input throughout the development of a TMDL.

Receive TMDL updates, including notifications to provide input, by email or text | Subscribe >

In Progress TMDLs

Queen Creek TMDL | Current Step: Data Review

Queen Creek and associated tributaries are impaired for copper and lead. ADEQ is working with a contractor to gather and analyze all available data to determine the best path forward.