What is plumbing rough-in?

Everything that will end up inside the walls, floors and ceilings:

• Drain, waste and vent (DWV) piping. The drain lines from each fixture location, the vent pipes that let air into the system, and the stack that ties them together and goes out through the roof.
• Water supply lines. Hot and cold lines from the water heater and main line to each fixture, capped at the stub-outs.
• Fixture stub-outs and supports. Drain openings set at the right distance from the wall, blocking for wall-hung fixtures, and the shower or tub valve body.
• Protection plates. Steel plates where pipes pass close to the edge of a stud or joist, so a nail or screw driven in later can't hit them.

Rough-in is a standard, named inspection stop, not just trade slang. DOE's Building America code brief, describing the energy code's inspection rules, says work under permit "is to remain accessible and exposed for inspection purposes until approved," and that "Required inspections include footing and foundation, framing and rough-in work, plumbing rough-in, mechanical rough-in, and final inspection." Our page on the permits and inspections new construction needs in Phoenix covers the full sequence.

### Where does rough-in fit in the job?

In the middle. On a slab home the plumbing happens in three passes. The underground pass puts in the building drain and any under-slab lines before the slab is poured. Rough-in comes after the framing is up, while every wall and ceiling is still open. Finish (or trim) comes last, after drywall, tile and cabinets, when the toilets, sinks, faucets and appliances are connected. In a remodel there may be no underground pass at all, but rough-in and finish still happen in that order.

### What about the protection plates?

They have a code section behind them. Section 305.6 of the 2024 International Plumbing Code applies in concealed locations where piping, other than cast iron or galvanized steel, goes through holes or notches in studs, joists, rafters or similar members less than 1-1/4 inches from the nearest edge. There, the pipe "shall be protected by steel shield plates" that cover the bored or notched area and extend at least 2 inches above sole plates and below top plates. Section 305.6.1 sets the plate thickness at not less than 0.0575 inch, which the code labels "No. 16 gage." We checked Phoenix's list of local IPC amendments (Ordinance G-7397, effective August 1, 2025), and 305.6 is not on it, so the model text applies in Phoenix.

From the fixture maker's specification sheets. The plumber sets each drain and supply stub-out to the dimensions the chosen fixture needs, which is why picking fixtures before rough-in saves rework.

The toilet is the best-known example. Toilet rough-in is the distance from the finished wall to the center of the drain, and the floor flange gets set at that distance during rough-in. TOTO's spec sheet for its Drake two-piece toilet lists a 12-inch rough-in, and its installation notes say: "To maintain adequate wall gap between the back of the tank and wall, mount the floor flange at a nominal 12” rough-in distance." Other models are made for other distances, so the flange goes where that specific toilet's sheet says. If you're replacing a toilet on an existing drain rather than building new, see how to measure a toilet rough-in before buying one. The space around the toilet matters as much as the drain; see toilet clearance code.

Sinks, showers and tubs work the same way. The faucet and valve maker's instructions set the drain height, supply height and valve depth, and the plumber builds to them while the wall is open.

Anything that moves a pipe. Once the plumber has drilled the framing and set the stub-outs, a change means cutting, re-drilling and sometimes re-testing. Before rough-in, settle:

• Every fixture model. Toilet, vanity, sinks, tub, shower valve and trim. Have the spec sheets on site, because the stub-out heights and the toilet flange distance come from them.
• Vanity and cabinet layout. The drain and supply stub-outs need to land inside the cabinet, not behind a drawer box or a side panel.
• Shower layout. Valve height, showerhead height, any handheld or body sprays, and where a niche or bench goes, so the pipes stay clear of it.
• Appliances that need water or a drain. Refrigerator ice maker, dishwasher, washing machine box, water softener or filter, and the water heater location.
• Anything you might add later. A future bathroom, a bar sink or a utility sink is far cheaper to stub out and cap now than to open finished walls for.
• Fixtures that are moving. In a remodel, every fixture that changes location needs new drain, vent and supply runs. See moving a toilet, sink or shower.

Walk the framed rooms with the plumber before the work starts and confirm each fixture location in place. It's the cheapest point in the job to change your mind.

The plumber tests the drain, vent and water lines for leaks, and the city inspects the work before anything covers it. Drain and vent piping usually gets a water test, and the water supply lines get a pressure test. In Phoenix, that check is part of the pre-drywall inspection, and the walls can't be insulated or closed until it's approved. Our page on the plumbing top out inspection covers the test rules, what the inspector looks for and why jobs fail. Chandler, for example, lists "733 Rough Plumbing/Topout" as its own inspection, separate from "730 U/G Water Piping" and "731 Building Drain."

After finish, the job gets one more check. See the plumbing final inspection for what happens at the end. If something fails at either stage, it gets fixed and re-inspected before the job moves on.

### What comes after rough-in?

Insulation and drywall, then the finish plumbing: setting toilets, mounting sinks and faucets, installing shower trim, and connecting the water heater and appliances. Drain slope is also set at rough-in, so if you want to know how that's checked, see drain pipe slope code.

Because it's the only time the plumbing is fully visible. Fixing a sloppy rough-in is easy with the walls open and a much bigger job after tile and drywall go up. A good rough-in means:

• Fixtures line up with cabinets, tile and the finished wall.
• Drains have proper slope and venting, checked while it's still easy to correct.
• Pipes stay protected from nails and screws.
• The inspection passes the first time, so the drywall crew isn't waiting.

HQ Plumbing & Air handles residential and commercial plumbing across the Phoenix area, including remodels and new work that need a rough-in inspection. We're licensed and insured, with free estimates and upfront pricing. See our residential plumbing services and commercial plumbing services.

Pipes in, tested, inspected, then the walls close. That's rough-in.