What is the minimum height a Pressure Vacuum Breaker (PVB) must be installed above ground?

A Pressure Vacuum Breaker (PVB) is a type of backflow prevention device that protects drinking water supplies from contamination. The fundamental requirement for the installation height of a PVB is to ensure that it functions correctly and remains effective at preventing backflow.

The minimum height for the installation of a PVB must be at least 12 inches above the highest point of the downstream piping. This height is critical because it helps to ensure that the device is free from any potential flooding or debris that could affect its operation. By maintaining this elevation, the air inlet valves that are part of the PVB can function properly, allowing for pressure relief and preventing siphoning conditions that could lead to contamination.

Installing the PVB too low could expose it to the risk of being submerged or blocked by vegetation or other materials, which could compromise the backflow protection it provides. Therefore, the requirement for a minimum height of 12 inches is established in plumbing codes and best practices for irrigation systems to ensure safety and compliance with public health standards.