New Construction Plumbing in Alpharetta, GA

On a large new home, the part of new construction plumbing that decides the most is the part nobody sees later: rough-in and top-out, when every drain, vent and supply line is run through open framing. A house with five or six bathrooms, an upstairs laundry and a kitchen island can hold a remarkable amount of pipe inside its walls before the first sheet of drywall arrives. In Alpharetta, that work also has to pass a city inspection before any wall is closed, so preparation pays off.

What happens at rough-in

Rough-in starts when the framing is complete and the house is dried in. The crew bores through framing within the limits the structure allows, runs drain and vent lines at the slope the code calls for, and brings hot and cold supply to each fixture location. Shower and tub valves are mounted at their finished height, tubs that must go in before the walls close are set, and stub-outs are capped. Where pipe passes close to the face of a stud, steel nail plates shield it from drywall screws. The order is no different from new construction plumbing on a modest house; on a big one each step simply takes longer.

What top-out adds

Top-out completes the vent system. Individual vents join in the attic and leave through the roof, ideally before the roofer finishes that slope so each pipe gets a proper boot. Larger homes often have more than one stack, and each route must clear ductwork, recessed lights and attic equipment platforms. With every opening capped, the system is filled with water or pressurized with air and held while the inspector watches for any loss.

Planning a big house so the pipes fit

• Stack bathrooms where you can. An upstairs bath above a downstairs bath shares a drain and vent path and keeps long horizontal runs out of the ceiling.
• Respect the joist direction. A drain that must cross engineered joists needs a planned chase or a soffit, not cuts made in the field.
• Think about hot water distance. A bath at the far end of a long house waits a while for hot water. A recirculation line, a second water heater or a tankless water heater serving that wing are common answers.
• Plan the island early. A sink in a kitchen island has no wall to carry a vent, so the venting method should be agreed with the inspector before rough-in.

How Alpharetta handles permits and inspections

Alpharetta's Construction & Inspections staff, part of Community Development, issue residential building permits, with plumbing permitted separately from electrical, HVAC and low-voltage work. Permit plans are submitted electronically, and inspections are requested by phone for a specific day. The city checks Georgia's contractor licensing rules before issuing a permit, though an owner working on their own home is one of the exceptions.

Because the request names a day, the plumbing has to be finished before the call, not nearly finished. The test should already be holding, and the inspector needs a clear path past other trades' materials.

The week between top-out and drywall

After approval, other trades are still in the walls with saws and drills. A short walk just before insulation catches a nicked line or a stub knocked loose by another crew. It is also a good time to confirm incoming water pressure; when street pressure runs high, a pressure-reducing valve protects the new fixtures, and our water pressure and PRV service covers that setup. Stubs should stay capped and labeled so the finish carpenter and countertop installer know which lines are live.

Rough-in and top-out questions in Alpharetta

What is the difference between rough-in and top-out?

Rough-in is the installation of drain, vent and supply piping inside open walls and floors, along with valves and tubs. Top-out completes the vent system through the roof and finishes the in-wall work so the whole system can be tested at once. Some builders treat the two as a single stage, while larger houses often get separate trips for each.

How are the pipes tested before the walls close?

Drain and vent piping is usually filled with water or pressurized with air, then left for a set period while the inspector checks for a drop or a visible leak. Supply lines are tested under pressure as well. The method and duration follow the code in force and the inspector's direction, so the plumber sets up whichever test the inspector expects to see.

Can fixture choices wait until after rough-in?

Some can, many cannot. Shower valves, tubs, wall-hung toilets, body sprays and floor-mounted tub fillers all need their rough parts in the wall or floor before drywall. Faucets that mount on a counter and most sinks can wait. A fixture schedule settled before rough-in avoids opening finished walls later.

Bringing your plans to Alpha

On a larger Alpharetta home, the sooner we see the drawings, the easier it is to fit stacks, supply runs and water heaters into the framing. Share your plans and timeline with us at (404) 409-4448.