What is the hydrostatic pressure of water per foot as stated?

• A. 0.5 per foot
• B. 1.0 per foot
• C. 0.2 per foot
• D. 2.0 per foot

Answer: (A)

Hydrostatic pressure grows with depth because the weight of the water above adds pressure at each level. Freshwater has a weight density of about 62.4 pounds-force per cubic foot. At one foot of depth, the pressure increase is 62.4 lbf/ft^2, which converts to 62.4/144 ≈ 0.433 psi. In practice this is rounded to about 0.5 psi per foot. So the stated hydrostatic pressure per foot is roughly 0.5 psi per foot. The other options would imply much higher or lower increases per foot than water actually provides.