Which device is used to prevent backflow into the public water system when water may be contaminated?

Which device is used to prevent backflow into the public water system when water may be contaminated?

• A. Deluge Valve
• B. Anti-Siphon Device
• C. Check Valve/Backflow Preventer
• D. Water Flow Indicator/Pressure Flow Preventer

Answer: (C)

Backflow prevention is about stopping contaminated water from flowing back into the public water system when pressures change or a cross-connection exists. The device that accomplishes this in the piping is a backflow preventer, typically a check valve that allows water to move only in the intended direction and automatically closes if flow tries to reverse. This one-way action protects the public supply from contamination, even if downstream conditions become hazardous or pressure drops occur. In fire protection and building systems, you might see simple check valves for low-hazard situations or more robust backflow assemblies for higher hazards, but the core idea is the same: prevent reverse flow into the potable water system. Deluge valves control sprinkler release rather than preventing backflow. Anti-siphon devices protect individual outlets from siphoning but don’t provide universal protection for the entire public supply. Water flow indicators or pressure flow control relate to monitoring or regulating flow, not stopping backflow into the system.

Backflow prevention is about stopping contaminated water from flowing back into the public water system when pressures change or a cross-connection exists. The device that accomplishes this in the piping is a backflow preventer, typically a check valve that allows water to move only in the intended direction and automatically closes if flow tries to reverse. This one-way action protects the public supply from contamination, even if downstream conditions become hazardous or pressure drops occur. In fire protection and building systems, you might see simple check valves for low-hazard situations or more robust backflow assemblies for higher hazards, but the core idea is the same: prevent reverse flow into the potable water system.

Deluge valves control sprinkler release rather than preventing backflow. Anti-siphon devices protect individual outlets from siphoning but don’t provide universal protection for the entire public supply. Water flow indicators or pressure flow control relate to monitoring or regulating flow, not stopping backflow into the system.