Most house plumbing work is priced by the fixture. The risk is not in the fixture itself but in what you find when you open things up.
Scope it first. Read any drawings, then walk the job and look under sinks, behind access panels and at the main shutoff. Note pipe material, shutoff condition, whether the drain and supply lines can be reused, and whether walls or cabinets must be opened. Confirm who supplies the fixture. Write down what is not included, like drywall repair, tile work or permits if the owner pulls them.
Count in the right unit. Fixtures, valves and appliances are priced each. List every one separately, even when two are in the same room, because each has its own connections.
Labor is hours times wage. For each fixture, estimate the hours to shut off, remove the old one, set the new one, connect, test and clean up. Multiply by the wage you actually pay, payroll costs included. Count drive time and supply-house runs; on small jobs they can be a big share of the day.
Material from public prices. Price fixtures, valves, supply lines, fittings and sealants from current retail or list prices you can look up. Add a small allowance for the extra fittings you always need.
Overhead, profit and contingency. Add your overhead and a profit you decided on ahead of time, as their own lines over direct cost. Carry a contingency for seized shutoffs, corroded pipe and old work that is not to code.
First-job checklist
- Who supplies the fixture, and is it on site
- Shutoff valves work, or price replacing them
- Pipe material and condition at the connection
- Access: open wall, cabinet or crawlspace
- Permit and inspection, if required where you work
- Test and leak check before you leave
Common mistakes
- Assuming the old shutoff will hold
- Leaving out wall or cabinet repair, or not excluding it
- Forgetting trips to the supply house
- Pricing a valve swap without the trim kit