Maricopa County, Arizona septic permits and requirements

Permitting authority

Maricopa County Environmental Services Department — Onsite Wastewater Program

Maricopa County Environmental Services, Onsite Wastewater Program; [email protected]; 602-506-6666. Applications and inspection requests are handled through the county Permit Center.

Arizona permitting framework

ADEQ has statewide authority for onsite wastewater treatment facilities and states that permitting authority is delegated to each of Arizona’s 15 counties. ADEQ rules continue to apply statewide, while delegated counties may have additional local requirements. Applicants should therefore use the county process for the property location unless the county or ADEQ identifies a project that remains under direct state jurisdiction.

State construction and discharge sequence

Arizona’s Type 4.02–4.23 general-permit framework covers many residential and light-commercial onsite systems up to 24,000 gallons per day. The state process requires authorization before construction and a discharge-authorization step after construction, inspection, and testing; county delegation and local limits determine which agency performs those steps for a particular project.

County permitting is divided into site-evaluation and design phases

Maricopa County publishes separate Phase I Site and Soils Evaluation and Phase II system-design processes. The county also maintains distinct application paths for conventional systems, alternative systems, alterations, closure or abandonment, minor plan review, ownership transfer, and final inspection.

Phase I establishes the soil absorption rate and site limitations

For a Phase I evaluation, the county requires the application and supporting documents, property and proposed-building locations to be marked, and test holes prepared for inspection. County Environmental Services evaluates the site and soils to establish the soil absorption rate and identify limiting conditions that affect system selection, sizing, and layout.

The county currently calls for three test holes for Phase I

Maricopa County’s current Phase I instructions call for three test holes approximately 12 feet deep: two in the proposed primary disposal area and one in the reserve area. Applicants should follow the current county packet because excavation and safety requirements are detailed there.

Design and construction follow the approved site evaluation

After Phase I results are issued, the owner or agent uses those results for the Phase II conventional or alternative system design. Construction or remodeling that involves onsite wastewater is subject to county application review and inspection rather than being authorized by the site evaluation alone.

Final inspection precedes discharge authorization

Maricopa County provides a Request for Discharge Authorization process for final inspection. The county directs applicants to complete the required final-inspection request before the system is placed into service, with reinspection requests handled through the Permit Center.

Official sources

SepticScope summarizes public-agency information for planning purposes. The permitting agency's current instructions control if they differ from this guide.