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Plumbing

Rough-In

In Plain English

The hidden plumbing pipes installed inside walls and floors before drywall is hung — the underground work that happens before fixtures are attached.

Definition

The installation of drain, waste, vent, and supply piping within the wall and floor framing before finish materials are applied, leaving stubbed-out connections at each fixture location. Rough-in dimensions specify the distance from walls and floors to fixture connection points (e.g., toilet rough-in is typically 12 inches from the finished wall to the flange center). All rough-in work is inspected before walls are closed.

Why It Matters in Bidding

Rough-in is a major milestone in plumbing, electrical, and mechanical bids because it sets the labor and material that gets buried before walls close, and it triggers a code inspection that must pass before drywall. Estimators must coordinate rough-in scope with other trades and the framing schedule, since missed connections or incorrect rough-in dimensions cause costly rework and change orders.

Example

A plumbing estimator takes off every fixture and prices the supply, drain, waste, and vent rough-in for a 12-unit apartment building, scheduling it to finish before the framer's walls are insulated and closed.

Related Terms

Drain-Waste-Vent (DWV)Supply LineCloset FlangeFixture Unit

Frequently Asked Questions

It covers the in-wall and below-floor supply, drain, waste, and vent piping run to each fixture location and capped or stubbed out, plus hangers, fittings, and the cost of passing rough inspection. Finish fixtures and trim are a separate, later phase. Coordinating rough-in dimensions with the architectural plans prevents rework.
Buried piping and connections are inaccessible once drywall is hung, so jurisdictions require inspection while the work is visible to verify slope, materials, pressure testing, and code compliance. Estimators should account for inspection holds in the schedule, because a failed rough-in inspection can stall the framing and finish trades behind it.
Rough-in for plumbing, electrical, HVAC, and low-voltage all compete for the same wall and floor cavities, so trades must sequence around framing. Estimators factor coordination time and potential conflicts into labor. Poor coordination drives change orders and delays, which is why MEP scope splits should be clarified during bidding.

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