Waters of Arizona

Frequently Asked Questions | WOTUS and WOAZ

What are Waters of the United States?

The Clean Water Act protects water quality across the country for what are considered Waters of the United States (WOTUS). WOTUS are generally defined as navigable waters and water bodies potentially connected to navigable waters within the boundaries of the United States. In Arizona, many of the waterways are drainages and/or ephemeral streams, which only run during or immediately after precipitation events. Jurisdictional status of these types of waterways in the current rule creates confusion for the regulated community and regulators within the State and across the country | Learn More >

I heard there is a proposed change to WOTUS. What is it? 

The Environmental Protection Agency (EPA) proposed a change to the WOTUS definition in early 2019 | Learn More >

The State sent a comment letter to the EPA and generally supports the proposed change | State of Arizona Comment Letter to EPA >

When will the EPA’s proposed WOTUS change go into effect?

The EPA is currently reviewing comments on the proposed WOTUS change. The final definition may differ from what was proposed. ADEQ anticipates that the EPA will publish a final WOTUS definition in early 2020, which would become effective 60 days after publication.

How will the proposed WOTUS change impact Arizona?

The proposed change would mean many waterways, lakes and ponds would no longer be regulated by the Clean Water Act. For example, drainages and ephemeral waterways (those that only have water in them after a storm event), would not be considered a WOTUS and would not be protected under the Clean Water Act. In Arizona, a significant portion of waterways are ephemeral. ADEQ estimates an 85 to 93 percent reduction of waterways, lakes and ponds protected under the Clean Water Act.

Protection of waters still part of WOTUS, as proposed, will continue through the Arizona Pollution Discharge Eliminations System (AZPDES) program, which requires dischargers to meet regulatory requirements of the Clean Water Act. WOTUS will also be monitored and protected as they currently are under additional Clean Water Act programs | List of ADEQ Permits >

Why is there only an estimate for the number of waterways, lakes and ponds no longer protected under the WOTUS change?

Determining which of these waterways or sections of these waterways are regulated under a new WOTUS definition will require a comprehensive review by ADEQ, EPA and other agencies.

What is ADEQ doing to protect the waterways if WOTUS changes?

The State will be responsible for protection of non-WOTUS surface waters in Arizona. ADEQ is in the early stages of gathering input and guiding principles for a Waters of Arizona (WOAZ) program. ADEQ values stakeholder, Tribal Nation and community engagement during program development and encourages your participation, if interested | Learn More >

What does the change mean to current permits issued for WOTUS in Arizona?

ADEQ anticipates that EPA’s proposed WOTUS rule will reduce the number of permits currently required by the Clean Water Act. However, until such time as the WOTUS definition is finalized and in effect in Arizona, there are no changes to permitting, and facilities with Clean Water Act permits must remain in compliance. ADEQ is also cautioning permittees against any significant changes to processes even if the WOTUS definition, as proposed, becomes effective. Non-WOTUS waters may be regulated under a State program. ADEQ is in the early stages of gathering input and guiding principles for a Waters of Arizona (WOAZ) program | Learn More >

What makes a waterway a ‘Waters of Arizona’?

Waters of Arizona, or "Waters of the State" as they are defined in statute, are “all waters within the jurisdiction of this state including all perennial or intermittent streams, lakes, ponds, impounding reservoirs, marshes, watercourses, waterways, wells, aquifers, irrigation systems, drainage systems, and other bodies or accumulations of surface, underground, natural, artificial, public or private water situated wholly or partly in or bordering on the state.”1 This generally means that all surface and groundwater resources within the state’s jurisdiction are considered Waters of Arizona.