H = p/(ρg) and p = ρgH
Near 20 °C with density about 998.2 kg/m³, 1 m of water is about 9.79 kPa and 1 ft of water is about 0.433 psi. Rounded field factors are useful only when their assumptions are understood.
Quick table near 20 °C
| Pressure | Metres of water | Feet of water |
|---|---|---|
| 10 kPa | 1.02 m | 3.35 ft |
| 100 kPa | 10.22 m | 33.53 ft |
| 1 bar | 10.22 m | 33.53 ft |
| 10 psi | 7.03 m | 23.07 ft |
| 50 psi | 35.16 m | 115.35 ft |
Gauge position and elevation
A gauge reading changes with elevation even in the same static water column. Record the gauge elevation and use pressure head plus elevation head consistently. Absolute pressure is required for vapor-pressure and NPSH work; most delivery-pressure calculations use gauge pressure.
Reference boundary. Do not convert an indicative value into a universal design, health or legal requirement. Check the cited source, laboratory context, certified claim and applicable jurisdiction.
Sources
- U.S. Geological Survey — Pressure transducers and pressure-head conversions
- NIST — Thermophysical Properties of Fluid Systems