Water Pressure Loss Calculator
Estimate Hazen-Williams pipe-friction loss, elevation loss, flow velocity and remaining pressure for a water line.
Default project preview
47.34 psi
Friction loss
6.16 psi
Elevation loss
6.5 psi
Total head loss
8.9 m
Flow velocity
4.08 ft/s
Calculator
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Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Hazen-Williams friction head = 10.67 × length × flow^1.852 ÷ (C^1.852 × inside diameter^4.871) in SI units. Elevation head is added before conversion to pressure.
FAQ
Water Pressure Loss Calculator questions
Why use actual inside diameter?+
Small diameter changes have a large effect on friction loss, and nominal sizes do not equal the inside bore.
What is the Hazen-Williams C factor?+
It is an empirical roughness coefficient; smoother pipe uses a higher value, while ageing and deposits can reduce it.
Does this account for water hammer?+
No. Surge and transient pressure require separate analysis and appropriate controls.