Skip to main content

Onsite Wastewater Treatment Facility

Groundwater | Engineering Review

Onsite Wastewater Treatment Facility

Revised On: Feb. 26, 2024 - 4 p.m.

Onsite Wastewater Treatment Facilities (OWTFs) are commonly known as septic systems and are widespread throughout Arizona. Today, there are estimated to be more than 600,000 systems in the State providing wastewater treatment for locations that do not have a sewer connection. When properly designed, installed, and maintained; an OWTF is an effective and safe method of treating wastewater. 

ADEQ has authority for issuing permits for OWTFs and has delegated this authority to each of the 15 counties, which issue permits on behalf of ADEQ.1

Apply for a Permit 

Before submitting a permit application, you may request clarification or interpretation of the statute, rule, delegation agreement, or substantive policy statement(s) related to the onsite wastewater treatment program | View Form >

Please submit your permit application to the county in which your property is located. See our Delegated County List | View List >

Delegate County Complaint

If you have a complaint regarding the ongoing implementation of the Onsite Wastewater Treatment Program by a delegated county, you may escalate your concerns to ADEQ | View Form >

Onsite Wastewater Advisory Committee

ADEQ established the Onsite Wastewater Advisory Committee (OWAC) to provide input and feedback on elements of the onsite wastewater treatment program including technical standards, innovative technologies, training and process improvements. 

  • OWAC Meeting Agendas and Notes | View >

You may request OWAC address a specific issue by emailing a description of the issue or question you would like OWAC to address. Requests are reviewed by the OWAC Chair and ADEQ | Email >

Get Involved | Modernizing the Program and Rulemaking

In January 2021, ADEQ began the process of updating A.A.C. Title 18, Chapter 9, as it applies to onsite wastewater treatment systems.2 To learn how you can get involved and stay current with rulemaking updates, visit the rulemaking page | Learn More >