In Arizona, onsite wastewater (septic) systems are regulated by Arizona Department of Environmental Quality (ADEQ), Water Quality Division — Onsite Wastewater Treatment Program, which sets the statewide code; some counties are delegated to issue permits and inspect locally, others are handled directly by the state agency. Installing, replacing or repairing a septic system here means, in sequence: a site and soil evaluation, a design, a permit application, an inspection while the system is open, and a final as-built record once it is approved.
The state-level regulator is Arizona Department of Environmental Quality (ADEQ), Water Quality Division — Onsite Wastewater Treatment Program (official program page). ADEQ holds statewide permitting authority for onsite wastewater treatment facilities (septic systems) and delegates issuance of standard/conventional permits to the health departments of Arizona's counties under individual delegation agreements; ADEQ directly issues permits for facility types or complex/large systems not covered by a given county's delegation agreement.
The statewide onsite-wastewater code is cited as Arizona Administrative Code, Title 18, Chapter 9, Article 3 (e.g. A.A.C. R18-9-A301, R18-9-A312, R18-9-A314 — General Permits for onsite wastewater treatment facilities). We link the agency's own page above rather than restating specific numeric requirements from it, since those change by rule revision and by local amendment.
The order of operations is broadly consistent across the country, even though the specific numbers in each step vary by state and often by county. None of the figures below are specific to Arizona; treat this as the shape of the process, and get the actual numbers from the agency linked above or from the county office.
| Design | Design documents for an onsite wastewater treatment facility must be signed, dated, and sealed by an Arizona-registered professional engineer (A.A.C. R18-9-A312); required site evaluations may be performed by a registered professional engineer, geologist, sanitarian, or an appropriately licensed septic/plumbing contractor. |
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| Installation | Installation requires an Arizona Registrar of Contractors CR-41 (Septic Tanks and Systems) license (roc.az.gov); qualified inspectors under A.A.C. R18-9-A314 must hold a CR-41 license, or be a Registered Sanitarian or Registered Engineer. |
Septic records in Arizona are generally held by the county or local health jurisdiction that issued the permit, not by the state agency, and are released under the state's public records law. We have not logged the specific statute name and response deadline for Arizona yet; check with the county office listed on its records page below, or with Arizona Department of Environmental Quality (ADEQ), Water Quality Division — Onsite Wastewater Treatment Program.
We hold 571,687 septic records across 4 of 15 Arizona counties. Each county page below shows exactly where its records are kept and how many we hold.
Full Arizona county-by-county index · Open the parcel map
Arizona Department of Environmental Quality (ADEQ), Water Quality Division — Onsite Wastewater Treatment Program. ADEQ holds statewide permitting authority for onsite wastewater treatment facilities (septic systems) and delegates issuance of standard/conventional permits to the health departments of Arizona's counties under individual delegation agreements; ADEQ directly issues permits for facility types or complex/large systems not covered by a given county's delegation agreement.
The sequence is a site and soil evaluation, a design sized from the evaluation and (under most state codes) bedroom count, a permit application, an inspection before backfill, and a final as-built filed once the system is approved. Exact numeric requirements are set by the agency's own code, not restated here.
Installation requires an Arizona Registrar of Contractors CR-41 (Septic Tanks and Systems) license (roc.az.gov); qualified inspectors under A.A.C. R18-9-A314 must hold a CR-41 license, or be a Registered Sanitarian or Registered Engineer.
Septic records are generally held by the county or district health office that issued the permit. See our county-by-county Arizona index for the specific office and portal in each county.
Regulatory information on this page was researched against official state agency sources and last verified 2026-08-31. It is informational only: the agency linked above is authoritative, and requirements can change. We are not lawyers, not a government body, and not affiliated with, licensed or certified by any agency named on this page.