Measure the actual water supply runs
A whole-house repiping estimate starts with the planned route of the hot and cold supply lines, not the square footage of the house. Two homes of the same size can require different pipe lengths because fixtures may be stacked on one plumbing wall or scattered across several floors. Measure each proposed route separately and count where the plumber will connect the new supply lines to fixtures and valves. This calculator combines the hot and cold footage for purchasing without losing the distinction between installed pipe and the extra material needed for cuts.
Fittings, shutoff connections and access repairs have their own quantities. A pipe order includes elbows, tees and couplings that cannot be estimated accurately from linear footage alone. Drywall or ceiling access may need patching even when the plumbing itself is complete. Enter the number of expected access openings from the contractor's scope, not the number of rooms in the building.
Repiping quantity and budget formulas
Purchased pipe (ft) = installed pipe × (1 + cutting waste % ÷ 100)
Pipe cost = purchased pipe × unit pipe price
Project subtotal = pipe + fittings + fixture connections + installation labor + opening patches + other quotes
Total allowance = subtotal × (1 + contingency % ÷ 100)
The labor rate is applied to installed pipe length, while the material rate is applied to the larger purchased quantity. If the contractor supplies an all-inclusive repiping quote, avoid filling both the detailed rate fields and the same charges in the other-work field. The resulting total is a sum of user-entered quotes, not an estimate of current local labor prices.
Worked example: hot and cold supply lines
A plan calls for 90 feet of hot-water pipe and 160 feet of cold-water pipe. The installed supply run is 250 feet. With a 10% cutting allowance, the theoretical purchase is 250 × 1.10 = 275 linear feet. If the supplier sells pipe only in fixed-length coils, check coil sizes before ordering; 275 feet is not necessarily a billable package quantity.
Suppose the project also requires 38 fittings, 10 fixture reconnections and eight access openings. Those counts remain separate from the 275-foot pipe purchase. A plumber may specify a different fitting arrangement after routing around obstructions.
What affects a repiping quote?
Pipe material, diameter, accessibility and distribution layout change the work involved. Running new pipe through an accessible basement is different from opening finished ceilings on two stories. Pressure testing, shutoff replacements, water-service connections, insulation, firestopping and restoration of finishes should be reconciled with the written scope. The calculator deliberately does not choose pipe diameter, determine code compliance or advise on the safe connection of a potable water system.
Repiping costs can also overlap with bathroom renovations or water-heater replacements. If one contractor has already included fixture disconnections or wall patching in another project, exclude those repeated amounts when combining budgets.
Whole-house repiping questions
Should I measure hot and cold pipes separately?
Yes. Fixtures and appliances do not all require both lines, and the routes often differ. Measure the proposed lengths separately before combining them for an overall purchase total. A licensed plumber should confirm routing, material and sizing.
Does repiping include replacing the water service?
Not automatically. The supply line from the utility connection or well to the building can be a separate excavation and service job. Include it only if the specified pipe quantities and written contractor quote expressly cover that work.
Why is the purchased pipe length higher than the installed length?
Purchased pipe allows for offcuts, changes of direction and unusable remnants. The calculator applies the waste percentage to supply length only; it does not increase fixture or fitting counts. Actual coil and stick sizes can change the final purchase order.