If you are building a house, the plumber shows up three times. Each visit has to be finished and inspected before the next trade can go. This is what happens at each one, and what you need to decide before it starts.
Phase 1: Underground
When: After the footings and foundation walls, before the slab is poured.
What happens: The plumber installs everything that will be under concrete. That is the main building drain, floor drains, drains for any basement bathroom, and the water service from the street.
Why it matters: This is the only phase that can’t be fixed later without a jackhammer. Drain pipe has to slope the right amount, the whole way. Every pipe that comes up through the slab has to land inside a wall that has not been built yet.
Decide before this phase:
- Will the basement ever have a bathroom? Stub the drains in now.
- Where is the water heater going? It may need a floor drain.
- Is there a floor drain in the garage or mechanical room?
The underground gets inspected before it is covered.
Phase 2: Rough-in
When: After framing and the roof, usually alongside the electrician and the HVAC installer, before insulation.
What happens: The plumber runs everything that will be inside the walls:
- Drain, waste and vent piping to every fixture, up through the roof
- Hot and cold water lines
- Gas lines to each appliance
- Tub and shower valves
- Tubs and shower pans, which go in now because they will not fit through a finished doorway
- Stub-outs for sinks, toilets, the fridge, the laundry and hose bibs
Then the system is tested. Drains are filled with water or air, and water lines are put under pressure, to prove nothing leaks before the walls are closed.
Decide before this phase:
- Every fixture. A wall-mounted faucet, a freestanding tub and a standard tub all rough in differently. The plumber needs the actual model, not “a tub.”
- Tank or tankless. A tankless water heater needs a bigger gas line and its own vent.
- Recirculation. In a large home, a recirculation line gets hot water to far bathrooms fast. It can only go in now.
- Soft water loop. Cheap now, and it lets you add a water softener any time.
- Extras. Pot filler, ice maker line, outdoor kitchen, a gas stub for a grill or fire pit.
Rough-in is inspected before insulation goes in.
Phase 3: Finish
When: After drywall, paint, tile, cabinets and countertops.
What happens: The plumber sets the things you can see. Toilets, sinks, faucets, shower trim, the disposal, the dishwasher hookup and the water heater. Everything is turned on, run and checked for leaks.
Then comes the final inspection.
Where builds get delayed
Three things cause most plumbing delays on a new home:
- Fixtures not picked. If the shower valve is not chosen by rough-in, the plumber has to guess or wait.
- Changes after rough-in. Moving a sink after the pipe is in means doing that part twice.
- A late bid. If it takes two weeks to get a plumbing number, the schedule is already behind.
What a plumber needs to bid your house
- Floor plans showing each fixture
- A site plan showing where the water and sewer connect
- A fixture list, or a note that you are supplying fixtures yourself
- Your water heater choice
- Your target dates
We turn new construction plumbing bids around in 1–3 days. Send us your plans and we will get you a number.