How must a double check be installed?

• A. Below grade
• B. Above grade
• C. On its side
• D. Vertically

Answer: (A)

Backflow prevention devices are placed where they stay protected from weather and tampering while still allowing testers to access the test cocks for annual checks. A double check valve assembly is designed to be buried in a valve box or installed in a dedicated below-ground enclosure. Installing it below grade keeps the assembly shielded from exposure and helps prevent freezing in cold climates, while still keeping the test ports reachable for maintenance and testing.

Choosing to install it above grade would expose the device to weather, damage, and potential freezing, and placing it on its side or vertically can complicate testing and proper seating of the internal valves. So the recommended placement is below grade.