What is the pressure increase per foot a scuba diver descends?

• A. 0.60 psi
• B. 0.44 psi
• C. 0.40 psi
• D. 0.50 psi

Answer: (B)

When a diver goes deeper, the water column above adds weight and increases pressure—this is hydrostatic pressure. In seawater, the pressure rises by about 0.445 psi for each additional foot of depth. A handy check is that 33 feet of seawater adds roughly 14.7 psi (one atmosphere) of pressure, so 14.7 psi divided by 33 feet is about 0.445 psi per foot. Rounding gives about 0.44 psi per foot, which is the standard approximation for seawater. The other numbers would imply a noticeably different water density, so they don’t match the real rate.