Skip to main content
Calcimator

Water Pipe Sizing Calculator

Size water supply piping based on fixture units, building height, available pressure, and pipe run length.

Inputs

FU

IPC Table 604.3: WC (tank) 2.2 FU; lavatory 1.0; shower 2.0; kitchen sink 1.4 per fixture

psi

IPC 604.1: minimum 15 psi at fixtures; IPC 604.5: maximum 80 psi (PRV required above 80)

ft

Results

Required Pipe Size

1 inches

Estimated Flow Rate12.9 GPM
Pipe Velocity5.27 fps
Friction Pressure Loss6.29 psi
How to Use This Calculator
  1. Enter total supply fixture units — use the Drainage Fixture Unit calculator to get this number.
  2. Set the number of building floors and available pressure at the meter.
  3. Enter the longest pipe run in feet from meter to the most remote fixture.
  4. Review Required Pipe Size and Pipe Velocity — velocity should stay between 4 and 8 ft/s.
  5. Check Friction Pressure Loss to ensure adequate residual pressure reaches the top floor.
Ad Placeholder

Related Calculators

Drainage Fixture Unit Calculator

Calculate total drainage fixture units and determine required drain, vent, and stack pipe sizes per plumbing code.

Gas Pipe Sizing Calculator

Size natural gas piping using the longest run method with Weymouth formula per IFGC standards.

Ad Placeholder