Where should a vacuum breaker be installed to prevent siphonage?

Where should a vacuum breaker be installed to prevent siphonage?

• A. At the lowest point in the system.
• B. On the main supply line, near the source.
• C. Beside each sprinkler head.
• D. Above the highest point in the system.

Answer: (D)

To prevent siphonage, place a vacuum breaker above the highest point in the irrigation system. When pressure in the lines drops, water can be drawn back into the potable supply if the device isn’t high enough. Putting the anti-siphon device above the system’s highest point ensures that any potential backflow must pass through an air inlet, which breaks the siphon and stops contaminated water from returning to the supply. If the device is at the lowest point, near the source, or beside each sprinkler head, a siphon could still develop in other parts of the run, allowing backflow to occur. Installing it high up provides a single, reliable protective point for the entire system.

To prevent siphonage, place a vacuum breaker above the highest point in the irrigation system. When pressure in the lines drops, water can be drawn back into the potable supply if the device isn’t high enough. Putting the anti-siphon device above the system’s highest point ensures that any potential backflow must pass through an air inlet, which breaks the siphon and stops contaminated water from returning to the supply. If the device is at the lowest point, near the source, or beside each sprinkler head, a siphon could still develop in other parts of the run, allowing backflow to occur. Installing it high up provides a single, reliable protective point for the entire system.