What is a plumbing final inspection?

At the end of the permitted work, after the required earlier inspections are approved and the installation is complete. Phoenix's residential checklist puts final inspection at the completed-structure stage. Confirm the required sequence and any outstanding items with the local building department, especially on commercial projects.

That puts it third in the usual sequence:

1. 1Underground, before the trenches are backfilled.
2. 2Rough-in or top out, with pipes exposed and the required drainage and supply tests ready for inspection. See what a plumbing top out inspection is.
3. 3Final, with the building complete.

Cities name and number it for scheduling. Phoenix's residential checklist uses Final Inspection (699), "to be performed when structure is complete and ready to occupy," and it covers building, electrical, mechanical, and plumbing at one visit. Chandler lists 745, Plumbing Final and Water Meter Verified. Our page on Chandler's required plumbing inspections lists its full sequence.

On a remodel or a single fixture job, such as a water heater replacement or a new gas line, the final may be the only inspection. The permit still isn't closed until it passes.

The finished system, with the fixtures in place and the traps filled. The IPC's final test for drainage is mostly visual. Section 312.5 says "The final test of the completed drainage and vent systems shall be visual and in sufficient detail to determine compliance with the provisions of this code." The inspector may run water, flush fixtures, and look under sinks. Where an inspector wants more than a visual check, the same section allows a smoke test: all traps are filled with water, "a pungent, thick smoke" is blown into the system, the roof vents are closed once smoke appears, and a pressure equal to a 1-inch water column is held for at least 15 minutes. Smoke coming out anywhere inside means a leaking joint or a dry trap.

Items that come up at almost every final:

### What about the gas test at final?

Phoenix checks the gas system at final on homes. Its checklist says: "Provide 3 lb. test at final for all gas piping. Gauge to be 1/10 lb. increments and hold pressure for 15 minutes." The plumber puts a gauge on the gas piping, pressurizes it, and the inspector confirms the needle hasn't moved. For any new gas piping, Phoenix's gas clearance table (TRT 00930) lists the city for the permit, the inspection, and the gas clearance that lets Southwest Gas turn service on. Our page on getting gas turned on after a city inspection explains that handoff.

### What about backflow at a commercial final?

Commercial buildings with a backflow assembly need a passing test before the final. Section 312.11.2 says reduced pressure, double check, and pressure vacuum breaker assemblies "shall be tested at the time of installation, immediately after repairs or relocation and at least annually," and that testing "shall be performed by a certified backflow assembly tester or repairer." Bring the test report to the final. See PRV vs RPZ valves for what each valve does.

### How do you get ready for the final?

Walk the job the day before, with the inspector's list in hand:

• Turn the water on and run every fixture. Look under each sink and behind each toilet for drips.
• Fill every trap, including floor drains and floor sinks, so they hold a seal.
• Find every cleanout, uncover it, cap it, and make sure the outside ones reach finished grade.
• Check each hose bibb for a vacuum breaker.
• Follow the water heater relief line to its end and confirm it drains through a visible air gap.
• Set up the gas test gauge if the job includes gas piping.
• Put permits, approved plans, revisions, and test reports where the inspector can see them.

It's bigger, and it's checked against a more detailed approved plan. On a restaurant, office, or retail build-out, the inspector usually confirms:

• Fixture count and type match the plans, including restrooms, drinking fountains, and service sinks.
• Grease interceptor is installed, sized as approved, and accessible for cleaning. See what city inspectors check on a grease trap.
• Indirect waste from ice machines, dish machines, and prep sinks drains through an air gap or air break where the code requires it.
• Backflow protection is in place for the service and for equipment like soda machines, boilers, and chemical dispensers.
• Water heater installation, including relief piping, expansion control, and gas venting.
• Accessible fixtures where the plans show them.

Commercial finals are often coordinated with the fire, health, and building finals, so one missed plumbing item can delay a certificate of occupancy and an opening date.

Items that can require correction include:

1. 1Missing vacuum breakers on hose bibbs, or a hose bibb without one added late.
2. 2Cleanouts buried or uncapped, often after landscaping or concrete covered them.
3. 3Water heater relief line problems: plumbed straight into a drain, reduced in size, or ending where the discharge can't be seen.
4. 4Gas test not set up or not holding.
5. 5Fixtures not finished: a missing trap, a toilet not caulked or not secured, a sink draining slowly.
6. 6Missing paperwork, such as a backflow test report or an approved revision for a moved fixture.

Follow the inspector's correction notice. The plumber corrects the items and requests the required reinspection. In Phoenix, inspections are requested by phone at (602) 495-0800, and the checklist says "Requests received before 9:00 p.m. (Monday-Friday) will normally be inspected the following workday."

### What if a permit was never finaled?

An open permit can surface when a building is sold, refinanced, or remodeled. The fix is to contact the city, find out what inspections are outstanding, and schedule the final. If the original contractor is gone, a new licensed plumber may be able to take over the permit, depending on the city. Our page on new construction plumbing permits in Phoenix covers who can pull and hold a permit.

HQ Plumbing & Air performs plumbing installation and testing and helps prepare for final inspections for commercial build-outs, tenant improvements, water heater replacements, and gas line work across the Phoenix area. We're licensed and insured, with free estimates and upfront pricing. See our commercial plumbing services.

Complete the permitted work, prepare the required tests and records, and have the local inspector determine whether the installation passes.