What is the height to the overflow of the tank in feet?

• A. 74.5 ft
• B. 18.3 ft
• C. 1,375 ft
• D. 42.5 ft

Answer: (D)

The height to overflow is the vertical distance from the tank bottom up to the point where water can spill out—the location of the overflow outlet sets how high the water can rise before overflowing. In this problem, the diagram or data shows the overflow outlet positioned at 42.5 feet above the tank bottom, so the maximum water depth before overflow is 42.5 feet. That also means the hydrostatic pressure at the bottom when the tank is full would be about 18.4 psi (since 1 ft of water ≈ 0.433 psi). The other values don’t match the indicated overflow position in the figure, so they don’t reflect the actual overflow elevation for this tank.