How to do a plumbing take-off from a fixture schedule

1. Start with the fixture schedule, not the floor plan

The fixture schedule is the contract for what you are installing. It lists each fixture type, its tag, and usually the manufacturer and model. Count from the schedule first, then verify against the floor plan — not the other way around.

If the schedule and the plan disagree, that is an RFI, not a guess. Carry the higher count and note the discrepancy in your bid qualifications.

2. Count by tag, not by symbol

Symbols repeat across sheets and get missed at sheet boundaries. Counting by tag — P-1, P-2, WC-1 — gives you a checkable list you can total per floor and reconcile against the schedule.

3. Split the work into phases

Underground, in-wall rough, and trim-out consume very different labor. Splitting them early gives you a defensible schedule of values and makes progress billing straightforward later.

• Underground: excavation, below-slab piping, sleeves
• In-wall rough: risers, branch piping, carriers, testing
• Trim-out: setting fixtures, trim, final test and punch

4. Price material before you price labor

Material pricing anchors the estimate. Once fixtures and pipe are priced, labor is a productivity question: how many hours per fixture, at what crew size, at what rate.

5. Add overhead explicitly

Insurance, fuel and administration are real costs on every job. Burying them in a single markup number makes it impossible to tell a losing job from a winning one. Break them out internally even if the customer only sees a total.

Common mistakes

• Counting from an outdated plan revision
• Missing fixtures at sheet boundaries or in mechanical rooms
• No allowance for permit fees or inspection re-trips
• Using last year's material pricing on a bid due next week
• One blanket markup instead of separated overhead and profit