When does a water main extension need ADEQ approval?

Before you start building. Arizona Administrative Code R18-5-505(B) bars a person from starting certain work before an Approval to Construct is issued by the Department. The work covered includes building a new public water system. It also includes changing an existing facility, "including an extension to an existing public water system." Any change that affects treatment, capacity, water quality, flow or distribution counts too. So a main extension to a city or water company system is squarely inside the rule.

The Approval to Construct is a review of the design before any pipe goes in. The applicant submits detailed construction plans, complete specifications and a design report. The report describes the work and its design basis. New water sources need extra analyses. The Department must act on a complete application within 30 days of receiving it.

A supplier proposing dilution of a contaminant through multiple sources also needs to examine the separate source-blending compliance approval. Its blending plan and downstream monitoring approval are not automatically supplied by general engineering review.

The Department approves an extension only for a system that meets the chapter's rules. A system that is making progress toward compliance on an approved schedule also qualifies. It issues the approval only when the plans show the system can reasonably be expected to meet the drinking water standards. In practice this is your engineer's design report doing the talking, so the utility's compliance history can matter to your schedule.

State law backs the rule with a fee and a plan requirement. A.R.S. 49-353 requires plans and specifications for public water systems, including distribution systems and distribution system extensions. It also caps the review fee: the Department cannot set a fee at more than its cost of providing the service.

R18-5-505 has exemptions from plan review for small projects on existing systems. Under R18-5-505(B)(3), an existing system in good standing is exempt from plan review for an extension that costs $12,500 or less. A water line that is not for a platted subdivision can also be exempt above $12,500 but under $50,000. That takes a design sealed and signed by an Arizona professional engineer, plus that engineer's review of the construction. After an exempt project, the water system files a notice of compliance. It lists a fair market value cost estimate, the design and review engineers, the completion date and the total construction time.

Those are the rule's numbers, and they apply to the water system that owns the extension. Project cost and system conditions decide whether an exemption applies. Plan on approval unless your engineer confirms an exemption in writing.

Two more provisions in R18-5-505 catch owners off guard:

1. 1An Arizona-registered professional engineer must prepare, or supervise, the plans, specifications and design reports. Each carries the engineer's seal and signature. An engineer not registered in Arizona may design an extension only if the total construction cost does not exceed $12,500.
2. 2An Approval to Construct becomes void unless the Department grants an extension of time within 90 days after any of three events: construction does not begin within one year of issuance, construction halts for more than one year, or construction is not finished within three years of starting. A project that sits on a shelf can lose its approval.

Yes. R18-5-507(A) says a person shall not operate a newly constructed facility until an Approval of Construction is issued by the Department. Before issuing it, the Department verifies that:

1. 1An Arizona professional engineer, or someone under the engineer's direct supervision, has finished a final inspection. A Certificate of Completion with the engineer's seal and signature is filed.
2. 2The construction conforms to the approved plans and specifications, and all changes are documented in record drawings under R18-5-508.
3. 3An operations and maintenance manual has been approved, if the project includes new water treatment facilities.
4. 4A certified operator, at a grade appropriate for each facility, is employed to operate each water treatment plant and the potable water distribution system.

Maricopa County describes the same handoff. Once construction testing, bacteriological reports and as-built documents are approved, an Approval of Construction certificate is issued. It is the operational permit for the system.

Maricopa County Environmental Services. The county's Subdivision, Infrastructure and Planning Program reviews pipelines in public rights-of-way. These include water distribution, wastewater collection and reclaimed water lines. It also reviews their pump stations and control structures. The submission is an application with fee, an Engineering Design Report, design drawings, specifications and supporting documentation. Water and wastewater treatment facilities go to a different program.

Phoenix's policy reflects the same structure. For main extensions outside city limits, plans go to the Water Services Department and also to Maricopa County Environmental Services and the local municipality. Outside Maricopa County, check with ADEQ and your county about who reviews.

They run side by side and neither replaces the other. A city can require its own plan review, permits and inspection for a main extension. Phoenix, for example, requires construction plans, fees and city permits before extension work begins. Scottsdale requires new mains to be flushed, pressure tested and disinfected and to pass microbiological testing before they are connected to the city system. The state approvals cover the design and the operating certificate, and the city covers construction standards and acceptance.

Put together, the sequence for a public main extension usually looks like this:

1. 1City plan review and permits for the extension.
2. 2Approval to Construct from ADEQ or the county reviewer before construction starts.
3. 3Construction to the approved plans, with city inspection.
4. 4Disinfection and bacteriological testing, then the engineer's Certificate of Completion and record drawings.
5. 5Approval of Construction, then connection and operation.

Customer-side piping may fall under plumbing permits rather than a public-main approval; confirm the system classification instead of deciding it from the meter location alone. Scottsdale's rules, for example, treat private water mains downstream of backflow prevention devices under MAG requirements with contractor oversight rather than as city mains. If your project has a long private main serving several buildings, ask your engineer which regime applies.

Ask your civil engineer two questions at the start of design: who is the reviewing authority for this main, and is the Approval to Construct part of the schedule? Then build in review time. The state's 30-day clock starts only when the application is complete. Our pages on who pays for a main extension and how a tap works show what comes before and after.

HQ Plumbing & Air handles the plumbing on your side of the connection, with a free estimate and the price up front. State rules change, so confirm the current requirements with ADEQ or your county.