ADEQ Water Quality Update on WOTUS

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Greetings Stakeholders,

The Navigable Waters Protection Rule which redefined Waters of the United States (WOTUS) went into effect on June 22, 2020. Several legal challenges are working their way through the courts, but as of this date there has been no stay of the rule in Arizona. As expected, ADEQ has received many questions on what this means for Arizona. Following is a brief update on current agency decisions and actions.

Informational Webinar

An informational webinar will be held in September to discuss these actions in greater detail. Webinar date, time and access information will be distributed in a later bulletin.

Determining WOTUS

Two initial screening methodologies are in development and will be used to determine if an Arizona water is a WOTUS and if a discharge will reach a WOTUS. These methodologies will be used on a case-by-case basis until further guidance and new tools are developed by the the US Environmental Protection Agency (EPA) and US Army Corps of Engineers (USACE). Additional information on the methodologies will be provided during the September webinar. 

Status of State Program

Development of the state surface water protection program has been temporarily suspended until the new methodologies can be used to define which Arizona waters will not be protected under the new rule. Once we have a better understanding of the gap, we will continue the state program planning efforts; our target date to restart that process is mid- to late October.

Protecting Arizona Waters

It is still ADEQ’s intent to seek legislation for new state program authorities during the 2021 legislative session. We are also preparing a plan on how to use existing authorities and enforcement discretion to protect uses of Arizona waters until a state program can be implemented. Additional information will be provided during the September webinar.

Thank you for your continued participation in collaborating with ADEQ to protect Arizona’s surface waters.


Trevor Baggiore
Water Quality Division Director
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