What permits does a septic system need, and what is the transfer-of-ownership inspection?

A new septic (onsite wastewater) system has to be permitted before it is built, and when a home on septic is later sold, Arizona requires a transfer-of-ownership inspection so the buyer knows the system works. Both processes run under the Arizona Department of Environmental Quality (ADEQ) rules in Arizona Administrative Code Title 18, Chapter 9 (R18-9), carried out locally in our area by Maricopa County Environmental Services. Knowing both ends of the system's life, the build permit and the resale inspection, helps you avoid surprises whether you are building or buying.

The regulatory framework

Onsite wastewater systems in Arizona are governed by ADEQ's rules in A.A.C. R18-9. ADEQ delegates day-to-day permitting to county agencies, so in the Phoenix metro your point of contact is usually Maricopa County Environmental Services rather than the state directly. Most conventional household systems are authorized under a general permit, while unusual designs or larger flows can require an individual permit. The county administers the applications, inspections, and approvals for your parcel.

Permitting a new system

For a new custom home, the septic approval generally moves through these stages:

1. Site investigation and soil evaluation. A percolation test and soil profile determine how quickly the ground absorbs water, which sets the system type and the size of the drainfield.
2. Design and application. A designer prepares the system to suit your soils, lot size, and household, respecting required setbacks from wells, property lines, structures, and washes. The application goes to the county.
3. Construction authorization. The county reviews and authorizes construction before the system is installed. You do not install first and ask later.
4. Installation and inspection. The system is built to the approved design and inspected before it is covered.
5. Approval of construction / discharge authorization. Once the system passes, the county issues the final approval that lets the system be placed into service.

Because the soil evaluation drives everything downstream, it belongs early in due diligence. A lot with poor percolation may require a more expensive engineered system, which changes both your budget and your site plan.

The transfer-of-ownership inspection

Arizona's rules add a step most buyers do not expect: when a property served by an onsite wastewater system changes hands, the system must be inspected as part of the sale. Under the R18-9 transfer-of-ownership provisions, the inspection is performed within a defined window before the closing (commonly up to six months prior), and the seller is generally responsible for having it done. The inspection confirms the system's condition and that it is functioning, and the report documents what was found.

After the sale closes, a Notice of Transfer is filed with the county or ADEQ within a short window (commonly 15 days), which formally moves the discharge authorization to the new owner. The practical points for each side are:

• For sellers: arrange the inspection in time, and be ready to address problems it surfaces, since an unresolved deficiency can complicate or delay the sale.
• For buyers: read the inspection report closely. It is your clearest window into whether you are inheriting a sound system or a repair bill, and it tells you the system type, which signals future maintenance.

Ongoing ownership

Septic systems are not install-and-forget. Conventional systems need periodic pumping and inspection, and engineered systems often carry a service contract. These are real ownership costs that the transfer inspection can help you anticipate before you buy.

How Jematell Homes helps

On a new build we coordinate the soil evaluation, the system design, and the county permitting, and we place the system to work with your home and any well. If you are weighing a parcel that already has a system, we can help you understand what the inspection and records are telling you. Because septic rules and fees are set under ADEQ and administered locally, and both change, we confirm the current requirements with Maricopa County Environmental Services for your parcel rather than assuming.