Approximately how many feet of head does 1 psi represent?

• A. 1.0 feet
• B. 0.5 feet
• C. 2.31 feet
• D. 4.62 feet

Answer: (C)

One psi represents about 2.31 feet of water head. Head measures how tall a column of water must be to produce a given pressure, using P = γ h. For water, the weight density γ is about 62.4 lb/ft^3. Converting 1 psi to psf gives 1 psi = 144 lb/ft^2. So h = P/γ = 144 / 62.4 ≈ 2.31 ft. Thus 1 psi corresponds to roughly 2.31 feet of head. The other numbers don’t fit because they would imply different pressure values: 1.0 ft is about 0.43 psi, 0.5 ft is about 0.218 psi, and 4.62 ft is about 2 psi.