Convert Feet of Water to Pounds per Square Foot
Convert Feet of Water (ftH₂O) to Pounds per Square Foot (lbf/ft²) instantly and accurately.
Conversion Formula
lbf/ft² = ftH₂O × 62.42796058
About Feet of Water
One foot of water column (ftH₂O) ≈ 2,989 Pa - the US customary equivalent of cmH₂O used in civil and hydraulic engineering. Municipal water supply systems are designed for 40-80 psi head ≈ 92-184 ft; fire suppression sprinkler systems require minimum 7 psi ≈ 16 ft. Well pump specifications, sump pump head ratings, irrigation mainline pressure, and drainage calculations all use feet of head. 1 ft of water = 12 in WC = 0.4335 psi ≈ 2,989 Pa.
About Pounds per Square Foot
One pound per square foot (psf) ≈ 47.88 Pa - the standard structural engineering load unit in US practice. Building codes specify design loads in psf: residential floors 40 psf; office buildings 50-80 psf; assembly areas 100+ psf; snow loads can exceed 100 psf. Wind pressure on building facades, soil bearing capacity for shallow foundations, and lateral earth pressure in retaining walls are all in psf. The related unit ksf (1,000 psf = 47.88 kPa) covers higher-capacity soils and deep foundations. 1 psf = 47.88 Pa.
Quick Reference Table
| Feet of Water (ftH₂O) | Pounds per Square Foot (lbf/ft²) |
|---|---|
| 1 ftH₂O | 62.428 lbf/ft² |
| 2 ftH₂O | 124.856 lbf/ft² |
| 5 ftH₂O | 312.14 lbf/ft² |
| 10 ftH₂O | 624.28 lbf/ft² |
| 25 ftH₂O | 1560.7 lbf/ft² |
| 50 ftH₂O | 3121.4 lbf/ft² |
| 100 ftH₂O | 6242.8 lbf/ft² |