Official sources checked August 30, 2026

Mohave County, Arizona septic permits and requirements

Arizona county-delegation framework

ADEQ states that it has statewide authority for onsite wastewater treatment facilities and has delegated permitting authority to each of Arizona’s 15 counties. ADEQ rules continue to apply statewide, while delegated counties may impose separate or stricter local standards. Applicants should submit through the county where the property is located unless a specific system remains under direct ADEQ jurisdiction.

Property transfer has a statewide inspection and notice process

Arizona requires an onsite-system inspection in connection with a property transfer and requires the buyer to submit the applicable Notice of Transfer within 15 calendar days after transfer. ADEQ identifies county-specific filing paths for delegated counties, so owners should use the current transfer instructions for the property location.

Development Services performs the delegated septic permit sequence

Mohave County states that ADEQ delegates the environmental-program authority to Development Services. The county monitors site investigations, reviews applications and installation plans, issues Construction Authorizations, inspects newly installed systems, issues Discharge Authorizations, and monitors ownership transfers.

Construction cannot start before the Construction Authorization is signed

Mohave County explicitly states that septic construction may not begin until the Construction Authorization has been signed by the applicant. Licensed contractors often handle permitting for owners, while owner-builders may submit the county application themselves.

Site investigation supports both system selection and sizing

The county requires percolation and soil evaluation before system installation because the site investigation provides the information needed to select and size the system. Mohave County maintains an approved site-investigator list and requires site-investigation notification before the investigation.

Alternative systems address documented limiting conditions

Mohave County explains that alternative systems are used when the site investigation finds limiting conditions such as high groundwater, high rock content, or soils that drain too quickly. The county publishes additional alternative-system requirements and an adjusted soil-absorption-rate chart.

Some parcels have an additional 50-foot property-line buffer tied to water availability

Mohave County states that in areas where public water is not available, the septic system must maintain a 50-foot buffer to any property line unless the property owners execute an agreement that is notarized and recorded with the deed.

County has separate alteration, abandonment, transfer, and larger-system paths

Mohave County publishes separate materials and fees for adding disposal area for increased flow, tank replacement, abandonment, transfer of ownership, alternative designs, and larger 4.23 systems. Its engineering-permit page requires stamped engineering construction plans for 4.23 onsite wastewater systems.

Official sources

• Arizona Department of Environmental Quality — Onsite Wastewater Treatment Facilities
• ADEQ — Delegation Agreements
• ADEQ — Notice of Transfer and Inspection
• Mohave County — Septic & Well Permitting
• Mohave County — Engineering Permits
• Mohave County — Environmental Quality / Waste Disposal

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