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WQD | Permit | OSWW Type 4.02 – 4.23 GP

Water Quality Division | Permitting

Onsite Wastewater Treatment System Type 4.02 – 4.23 General Permit (GP)

Revised On: Feb. 27, 2024 - 7:30 a.m.

This permit is for septic systems with flows from 0 to 24,000 gallons per day, including standard onsite and alternative systems. They are most commonly used in residential applications. However, they may be used in light commercial applications including schools, RV parks, strip malls and small subdivisions. Almost any facility that needs to dispose of wastewater flows associated with typical sewage where sewer is not available (or is covered by an Individual APP). This permit is valid for the life of the facility.

The permitting process requires applicants to submit a Notice of Intent to Construct an onsite wastewater treatment facility that meets state design requirements. When an application is approved, construction is authorized and the applicant is given two years to construct the facility. Once construction, inspection, and testing of the facility is complete, the applicant submits a Notice of Intent to Discharge. A Discharge Authorization is issued once all the requirements for the design, construction, testing, and operation are verified. 


The following provides information to help permittees meet Onsite Wastewater Treatment System requirements:

Arizona’s statewide inspection program for onsite wastewater (septic) treatment facilities inspection are triggered by the resale of a home by an 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 onsite system.


  • The seller of a property served by a conventional septic tank or alternative system shall retain a qualified inspector to perform the transfer of ownership inspection within six months before the date of property transfer.
  • The inspector shall prepare a Report of Inspection (ROI) form, and provide it to the seller of the property. The ROI is not filed with ADEQ, as it involves communication on the status of the onsite wastewater system between the transferor/seller and the transferee/buyer.
  • The seller shall provide the buyer with the completed ROI form and any documents in the seller’s possession relating to permitting, operation, and maintenance of the onsite system.
  • Within 15 calendar days after the date of property transfer, the buyer shall submit a completed Notice of Transfer (NOT) form for the change of ownership and file the NOT with the proper agency.
    • For properties located in Coconino, Maricopa, Pima, and Yavapai counties view the NOT form for instructions on how to submit the NOT | View Form > 
    • For properties located in all other counties, NOT should be submitted online | View Form > 

The list of proprietary and other reviewed products may include manufactured systems, subsystems or components within the treatment works and disposal works if the products significantly contribute to the treatment performance of the system or provide the means to overcome site limitations. The designer must select treatment systems from this list based on identified site-limiting conditions and applicant requirements | View List >

Unsure where you need to submit your Engineering Review documents and applications?

See ADEQ's listing of Delegated Agencies | View Listing >