A pressure vacuum breaker must be installed a minimum of how many inches above the highest point of usage?

The correct answer indicates that a pressure vacuum breaker should be installed a minimum of 12 inches above the highest point of usage. This requirement is crucial for ensuring proper backflow prevention in plumbing systems.

The installation height is mandated to create sufficient air gap between the pressure vacuum breaker and the highest water outlet. This positioning allows for the effective prevention of back siphonage, which can occur if there is a loss of pressure in the water supply system. By having this minimum space, it ensures that any potential contaminants that may siphon back into the potable water supply do not have a route to reach the water at the highest outlet.

This standard is in place to protect public health by maintaining safe drinking water and to adhere to best practices in plumbing system design. Meeting this requirement not only complies with the plumbing code but also promotes the reliability and safety of the plumbing system overall.