Backflow Prevention Practice Exam

Atmospheric vacuum breakers are designed to prevent backflow and protect the potable water supply from contamination. They must be installed above the highest point of use to ensure their effectiveness. This placement allows the atmospheric vent to function properly, preventing siphoning effects that could draw contaminated water back into the clean water supply.

By being installed above the highest point, the atmospheric vacuum breaker can break the vacuum that may create a negative pressure situation in the system, effectively blocking any potential backflow. This is critical to maintaining safe and clean drinking water, as it leverages gravity and air pressure dynamics to safeguard against contamination.

In contrast, locations such as underground or below ground level are not permissible for installation due to their susceptibility to flooding and inability to function effectively in a vacuum condition. Additionally, installation at all plumbing fixtures is impractical, as applying vacuum breakers selectively at points where backflow could occur is both efficient and sufficient.