A plumber is replacing an existing water heater in a commercial building. The building's potable water supply is classified as a moderate hazard due to the nature of the business operations. Which type of backflow prevention device, if any, is typically required immediately downstream of the water meter for the entire building distribution system according to NPC standards?

Question: A plumber is replacing an existing water heater in a commercial building. The building's potable water supply is classified as a moderate hazard due to the nature of the business operations. Which type of backflow prevention device, if any, is typically required immediately downstream of the water meter for the entire building distribution system according to NPC standards?

Answer options:

• No specific device is required for moderate hazard buildings.
• Atmospheric Vacuum Breaker (AVB) ✅ Double Check Valve Assembly (DCVA)
• Pressure Vacuum Breaker (PVB)

Correct answer: Double Check Valve Assembly (DCVA)

Explanation: For potable water supply systems classified as a moderate hazard, the National Plumbing Code typically requires a Double Check Valve Assembly (DCVA) to protect against backflow. An AVB or PVB are generally for lower hazard ratings or specific fixture isolation against back-siphonage only. No device would be acceptable for a moderate hazard.