On suction piping, when the pump is above the water level, which component is used to hold the prime?

• A. Check Valve
• B. Foot Valve
• C. Gate Valve
• D. Air Valve

Answer: (B)

When the pump sits above the water surface, you need a valve at the end of the suction line that prevents water from flowing back out of the line when the pump stops. A foot valve is designed for this exact role: it’s a check valve installed at the suction inlet in the water that opens to let water reach the pump and then closes to hold the water in the line, thereby preserving prime. It often includes a screen to keep debris out, which helps maintain a clean suction. Gate valves aren’t used to retain prime—they’re for isolating sections of piping. An air valve is for venting trapped air and aiding priming, not for holding water in the suction line. A general check valve could serve to prevent backflow, but the foot valve is the specific device used at the suction end to maintain prime.