How Do You Bid a Plumbing Job?
Work the bid in the order of the checklist above. The takeoff comes first because everything else hangs on it, and you can't price labor on pipe you haven't counted.
Take off by system and by size, never as one lump of pipe. Domestic water, sanitary waste and vent, storm and gas use different materials and different labor, and the general contractor will compare your number line by line against the other plumbing bids.
How to Bid Plumbing on New Construction
New construction plumbing runs in phases, and pricing it by phase keeps the bid clear and the billing simple later:
- Underground: below-slab waste, storm and water lines, plus excavation and backfill if you carry them
- Rough-in: piping in the walls and ceilings before they are closed
- Top-out: vents through the roof and the tie-ins above the rough-in
- Trim or finish: fixtures, trim, water heaters and startup
Most of the labor sits in underground and rough-in, where the pipe and fittings are. Fixtures cost more as material, but they go in fast.
Pricing the Labor
Labor is priced separately from material. Most estimators price it with labor units, the hours to install one fitting, one foot of pipe or one fixture, taken from published manuals such as the MCAA (Mechanical Contractors Association of America) labor estimating manual or from their own job cost history.
Adjust the units for the job in front of you. Work above a certain height, work in an occupied building, overtime and long material hauls all slow a crew down, and your own completed jobs are the best check on whether your units are right.
The Scope Letter
The scope letter states exactly what your price covers. List what you include by system, what you exclude, and any clarification about the drawings.
Common exclusions on commercial plumbing are excavation and backfill, concrete cutting and patching, fire protection, equipment furnished by others, and utility company fees. If the drawings show it and you didn't price it, say so in writing.
Common Mistakes on a Commercial Plumbing Bid
The one that costs the most is pricing from the floor plans without reading Division 22, because the specification decides the pipe material, the joint type, the insulation and the testing, and each of those moves the price.
The other regulars are missing an addendum, leaving out below-slab piping, counting pipe but not fittings, forgetting hangers and supports, and using labor units from a job nothing like this one.
