On-Site Wastewater Treatment

On-site Wastewater Treatment

On-site wastewater treatment refers to a conventional septic tank system or alternative system installed at a site to treat and dispose of wastewater, predominantly of human origin, generated at that site. ADEQ has authority for issuing permits for operating these systems. 

Program Summary

The permitting program requires applicants to submit a Notice of Intent to Construct an on-site wastewater treatment facility that meets specific design requirements found in the Arizona Administrative Code (AAC). The regulatory agency approves the construction plans and issues a Construction Authorization to the applicant, giving the applicant two years from the issuance date in which to construct the on-site wastewater treatment facility.  Once construction, inspection, and testing of the on-site wastewater treatment facility is complete, the applicant will submit a Notice of Intent to Discharge.  The regulatory agency will issue a Discharge Authorization to the applicant once all the requirements for the design, construction, testing and operation are verified.

Why do I need a permit? Learn more >

Delegated Authority

We delegate regulatory functions for on-site wastewater systems to county environmental and health departments. If seeking a permit for an on-site system, please apply to the county in which the property is located.

Not sure who to submit your engineering review paperwork to?

See listing of delegated agencies >

Notice of Transfer and Inspection

Arizona’s statewide inspection program for on-site wastewater (septic) treatment facilities requires inspection upon the resale of a home by the owner or with the assistance of a real estate professional. The inspection requirement applies to any property served by a conventional septic tank system or an alternative on-site system.

Learn about the Inspection Program >

5-Year Program Improvement Plan

We are committed to improving the on-site wastewater treatment program, including rules, procedures and policies, in order to better support county partner and customer needs. Consider our 5-Year Plan the roadmap to the program's future, providing direction for the timely implementation of improvements to fulfill our commitment to stakeholders.

5-Year Plan | View/Download >

Projected Milestone Schedule

Initial Rulemaking:                                  Q1 2021 – Q1 2022
Ongoing Program Improvements:    Q1 2021 – Q4 2021
Technical Workgroups:                          Q1 2021 – Q4 2023
Additional Rulemaking (if needed):  2024
Implementation and Evaluation:       2025

Updates to Existing Rules

In January 2021, ADEQ began the process of updating AAC Title 18, Chapter 9, as it applies to on-site wastewater treatment systems.1 To stay current with rulemaking updates, please visit our stakeholder engagement page | View stakeholder page >

On-Site Wastewater Advisory Committee

ADEQ established the On-site Wastewater Advisory Committee (OWAC) to provide advice on the On-site Wastewater Treatment program defined in AAC Title 18, Chapter 9 and primarily delegated to Arizona Counties pursuant to Arizona Revised Statues (ARS) 49-107.2 ADEQ may seek input and/or feedback from OWAC members on the following items.

  • Technical standards for the design, installation, operation and maintenance of systems.
  • New or innovative technologies, materials and designs related to onsite wastewater treatment and disposal systems that maintain and advance protection of public health and water quality.
  • Technical issues to improve the efficiency of the regulatory program.
  • Educational and training programs to improve the overall knowledge of owners and operators.
  • Installation, operation and maintenance of onsite wastewater treatments systems, including graywater systems.
  • Potential changes to program rules.

OWAC Meeting Agendas and Notes | View >

Do You Have a Question for OWAC?

You may request to have OWAC address a specific question or issue by contacting one of the current members or by emailing a request | Email > 
Please describe the issue or question you would like OWAC to address and include your contact information so we may follow-up with you. Requests will be reviewed by the OWAC Chair and ADEQ.

Technical Work Groups

ADEQ will form six technical work groups to assist in implementation of the 5-Year Plan:

Each work group has a charter specific to the group’s scope of work and includes issues the group will address. All groups, except one, will recommend changes to the existing regulatory program. The Ideal Future State Exploration work group will focus on potential frameworks for a regulatory program with more flexibility and potential for treated water reuse.

White Paper Outline | View/Download >
Issue Prioritization Worksheet | Download Excel Spreadsheet >

How to Apply

We are now accepting work group membership applications online. Please apply by 5 p.m. Tuesday, April 6, 2021 | Apply Now >

We intend to select applicants based on technical expertise, availability and geographic diversity. 

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