Plumbing and electrical rough-in costs: the systems inside the walls

What the systems stage includes

Note the "except fixtures" in both lines. Faucets, toilets, sinks, tubs and showers are counted in plumbing fixtures ($7,922), and light fixtures in lighting ($5,392), both in the interior finishes stage.[1] When you compare a plumber's or electrician's quote with these figures, check whether fixtures are in or out.

Both trades have grown as a share of construction cost over the past decade. Plumbing went from 4.8% in 2013 to 5.8% in 2022 and 6.3% in 2024; electrical from 4.0% to 6.1% and then 6.4%.[1]

Plumbing rough-in: what drives the cost

Plumbing rough-in covers the water supply lines, drain and waste lines, vents, the water heater connections, gas piping where used, and the connection to the public system or septic. The main cost drivers are:

• Number of fixtures and bathrooms. Each sink, toilet, shower, tub, laundry and outdoor tap adds supply, drain and vent work.
• Layout. Bathrooms stacked above each other, or back-to-back with the kitchen or laundry, share drain stacks and keep runs short. Spread-out wet rooms cost more.
• Foundation type. On a slab, drains are placed before the concrete is poured, so locations must be final early. Crawl spaces and basements allow more flexibility. See foundation types.
• Water heating. Tank, tankless or heat pump water heaters have different venting, power and space needs.
• Special features. Island sinks, pot fillers, body sprays, steam showers, water treatment and recirculation pumps all add work.
• Site connection. Distance to the street connection, or a well and septic system. See well and septic costs.

Electrical rough-in: what drives the cost

Electrical rough-in covers the service entrance and panel, circuits, wiring, boxes for outlets, switches and fixtures, and low-voltage wiring if included. The cost depends on:

• Service size. All-electric homes, electric vehicle charging, heat pumps and large appliances raise the load and may need a larger service and panel.
• Number of devices. Every outlet, switch, light and dedicated circuit adds labor and material.
• Lighting design. Recessed lighting, multiple switching locations and smart controls add boxes and wiring.
• Code requirements. The electrical code sets minimum outlet spacing, protection devices and circuits for kitchens, baths and laundry. Your jurisdiction's adopted code edition matters.
• Low-voltage systems. Data, security, speakers and cameras are often priced separately.
• Future-proofing. Conduit to the attic for solar, a circuit for an EV charger and spare panel capacity are cheap now and costly to add later.

Licensed trades, permits and who pays for what

Plumbing and electrical work on a new house is usually done by licensed contractors, and many jurisdictions issue separate trade permits for each, in addition to the building permit. Even where owner-builders are allowed to pull their own building permit, some places still require licensed trades for these systems. If you are acting as your own contractor, ask your building department before you plan to do any of this work yourself; see being your own general contractor.

Check how each quote handles the edges of the job. Does the plumber's price start at the house or at the street connection? Does the electrician's price include the temporary power pole during construction, the meter base and the trench to the service, or are those the utility's or the site contractor's work? Who pays the utility's connection charges? Gaps here are common in bids and show up later as extras.

Water heaters and gas lines

The water heater decision affects both trades. A gas tank or tankless heater needs a gas line and venting; an electric or heat pump water heater needs a dedicated circuit and, for heat pump models, enough space and air around the unit. Placing the heater close to the kitchen and main bathrooms shortens the wait for hot water and reduces pipe runs.

If you use gas for heating, cooking or water heating, the plumber or a gas fitter runs the gas piping inside the house, and the gas utility usually installs the service line and meter. If gas is used for only one appliance, compare the cost of bringing gas to the house against an all-electric option. Ask the utility for its connection charge in writing, because it is often billed separately from your builder's price, and ask your builder which of the gas work is in their bid.

The pre-rough-in walk-through

The single most valuable hour you can spend on a new build is walking the framed house with the electrician, and ideally the plumber, before they start. Bring your furniture plan and your appliance list and mark:

• Outlet locations behind beds, desks, TVs and kitchen islands, and any floor outlets.
• Switch locations and which lights they control, including three-way switches at stairs and long halls.
• Light fixture locations, especially over tables and islands, so they center on the furniture.
• Exterior outlets, lights, doorbells and cameras.
• Appliance specs: power, gas, water and drain needs for the range, refrigerator, washer and dryer.
• Plumbing fixture locations and heights, including shower valves and niches.

Rough-in inspections

Plumbing, electrical and mechanical rough-ins are inspected by the building department before the walls are closed. Plumbing systems are often pressure-tested; electrical work is checked for proper wiring, boxes, protection and grounding. A failed inspection stops work on that area until it is corrected and re-inspected, which can hold up insulation and drywall.

Ask your builder to tell you when inspections are scheduled and to share the results. Take photos of every wall after the rough-in inspection and before insulation. They will help you find pipes and wires later when hanging shelves or making repairs, and they are useful records if a problem appears.

Ways to control plumbing and electrical costs

• Stack bathrooms and keep wet rooms close together.
• Put the water heater near the kitchen and bathrooms to shorten hot water runs.
• Finalize kitchen and bathroom layouts before the foundation if you are building on a slab.
• Choose a lighting plan with your electrician rather than adding fixtures room by room later.
• Price low-voltage and smart-home wiring separately so you can decide what you really need.
• Ask for unit prices for extra outlets and lights so changes are priced fairly.
• Use standard fixture rough-in sizes unless you have already chosen a special fixture.
• Keep the laundry near a bathroom or the kitchen so it can share drain and vent lines.

Do not cut the infrastructure you will need later. Spare circuits, a larger panel or conduit for future wiring cost little during construction. Wet-area waterproofing, venting and proper drain slopes are not places to economize.

Budgeting in the calculator

In the calculator, the Major Systems Rough-ins stage has separate lines for plumbing, electrical, HVAC and other systems. Start with the NAHB averages, then enter quotes as lump sums. A house with many bathrooms or a high electrical load will take more than the national 19.2% share. For the third system in the stage, see HVAC costs for a new house, and for fixtures and lighting see interior finishes.

Frequently asked questions

Sources

1. NAHB: Cost of Constructing a Home 2024 Verified

Figures last checked October 18, 2026. National averages are a planning guide, not a quote. See our editorial policy and data sources.