What is the approximate hydrostatic pressure (in psi) at a depth of 124.7 ft of water?

• A. 53 psi
• B. 54 psi
• C. 60 psi
• D. 70 psi

Answer: (B)

As you go deeper in water, the pressure increases because the water column above adds more weight. The hydrostatic pressure can be calculated with P = γh, where γ is the unit weight of water. For freshwater, γ is about 62.4 lb/ft^3, which is equivalent to roughly 0.433 psi per vertical foot (since 62.4 lb/ft^3 divided by 144 in^2/ft^2 gives psi per foot).

Compute the pressure at 124.7 ft:

P ≈ 0.433 psi/ft × 124.7 ft ≈ 54 psi.

So the approximate hydrostatic pressure is about 54 psi.