Which component prevents reverse flow in a discharge line?

• A. Pressure relief valve
• B. Globe valve
• C. Check valve
• D. Strainer

Answer: (C)

A check valve is used to prevent reverse flow in a discharge line. It allows water to move in the intended direction—from the pump toward the system—and automatically seals shut if flow tries to go backward. This stops the discharge piping from draining back toward the pump when the pump is off or system pressure falls, protecting the pump and preserving system pressure.

Other components have different roles: a pressure relief valve vents excess pressure rather than preventing backflow; a globe valve controls or blocks flow but isn’t primarily a backflow device; a strainer removes debris and does not affect flow direction.