Backflow Prevention Practice Exam

The plumbing code requires that a spill-resistant vacuum breaker be installed above the highest use by at least _____?

1. 3 in. (7.6 cm)

2. 6 in. (15 cm)

3. 9 in. (23 cm)

4. 12 in (30 cm)

The correct answer is: 12 in (30 cm)

The plumbing code specifies that a spill-resistant vacuum breaker must be installed above the highest use by at least 12 inches (30 cm) to ensure proper protection against backflow and potential contamination of the potable water supply. This height creates a sufficient physical separation between the device and the water supply, which is crucial in preventing any possible back siphonage or reverse flow that could introduce contaminants into the drinking water system. The requirement for a minimum distance emphasizes the importance of maintaining an adequate air gap, which is fundamental in backflow prevention strategies. This specific height helps to mitigate risks associated with any pressure fluctuations in the water supply, ensuring that the vacuum breaker functions effectively to protect public health. Other height options do not provide the same level of safety and assurance against backflow risks, thus underscoring the necessity of adhering to the code’s 12-inch requirement for installation.