What component is encountered immediately after the pump on the discharge side?

• A. A gate valve
• B. A check valve
• C. A relief valve
• D. A diaphragm valve

Answer: (B)

After the pump, the discharge line is typically protected by a check valve. A check valve is a one-way device that lets water flow away from the pump but prevents any reverse flow back toward the pump. This prevents backflow that could move contaminated water into the source, keeps the pump from losing its prime, and reduces the risk of damage from reverse pressure when the pump stops or the downstream system pressure drops. While a gate valve might be used to isolate the pump for maintenance, its primary role isn’t to stop reverse flow. A diaphragm valve is mainly for throttling or flow control in smaller lines, and a relief valve is used to vent excess pressure, not to prevent backflow in normal operation.