What type of standard backflow protection device is required for a hose union bib tap?

• A. Double check valve
• B. Check valve
• C. Ball valve
• D. Backflow preventer

Answer: (A)

Backflow protection is needed on hose connections because a suction or pressure change can pull potentially contaminated water back into the potable supply through a hose. For a hose union bib tap, the standard protection is a double check valve. This device uses two independent check valves in series and includes test ports, so it provides redundancy and allows testing to ensure it’s sealing properly. If one valve leaks, the other still blocks reverse flow, and you can verify functionality. A single check valve isn’t enough because it lacks that redundancy and testability. A ball valve is just a shutoff and doesn’t prevent backflow. A generic backflow preventer term can refer to other devices, but the required and commonly accepted option for a hose bib is the double check valve.