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Plumbingaka: sinkaka: bathroom sinkaka: hand sinkaka: wash basin

Lavatory

In Plain English

A bathroom sink designed for washing hands and face.

Definition

A plumbing fixture designed for handwashing, installed in bathrooms or restrooms and connected to both hot and cold water supply and a drain. Lavatories come in undercounter, drop-in, wall-hung, and vessel configurations. The plumbing code specifies required clearances, mounting heights, and the number of lavatories required based on occupancy.

Why It Matters in Bidding

Lavatory counts are driven by occupancy-based plumbing-fixture requirements, so an estimator must price the right quantity or risk a non-compliant design and rework. Each lavatory carries hot and cold supply, drain, trap, faucet, carrier, and accessibility clearances, making the per-fixture rough-in and trim cost a meaningful and easily underestimated piece of the plumbing bid.

Example

A plumbing estimator counts wall-hung lavatories per the fixture schedule and adds concealed carriers and ADA clearances when pricing a commercial restroom rough-in.

Related Terms

P-TrapRough-InFixture UnitSupply Line

Frequently Asked Questions

In plumbing terms a lavatory is specifically a bathroom handwashing fixture, while sink usually refers to kitchen, utility, or service fixtures. The distinction matters for takeoff because lavatories follow restroom fixture-count and accessibility codes, and the two fixture types carry different faucets, drains, and rough-in details that affect pricing.
Installed cost reflects the fixture and faucet, hot and cold supply rough-in, drain and trap, mounting type, and labor. Wall-hung units add concealed carriers, and ADA restrooms require specific clearances and insulated traps. Counting only the basin and ignoring carriers, trim, and accessibility work is a common way to underbid.
The plumbing code sets minimum fixture counts based on occupancy type and load, so estimators verify quantities against the fixture schedule and the building's occupancy classification rather than guessing. Confirming the required count early avoids pricing a non-compliant design that triggers redesign, change orders, or inspection failures later.

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