Cross Connection Practice Exam

What type of backflow preventer is required for a water line serving a sewage treatment area?

1. Reduced Pressure Principle Assembly

2. Approved Air Gap

3. Double Check Valve Assembly

4. Pressure Vacuum Breaker

The correct answer is: Approved Air Gap

Choosing an approved air gap is essential for a water line serving a sewage treatment area because it provides the highest level of protection against backflow contamination. An air gap is a physical separation between the end of a potable water supply line and the flood level of the receiving vessel, which effectively prevents any potential backflow from the sewage treatment activities into the drinking water supply. This method ensures that even in the most extreme situations, where pressure changes might create risks of back siphonage, there is no possibility for any contaminated water to reach the potable water supply. The air gap creates a barrier that backflow cannot cross, making it the most reliable choice for situations involving wastewater or sewage treatment. In contrast, while other devices like the reduced pressure principle assembly, double check valve assembly, and pressure vacuum breaker are effective backflow preventers, they do not provide the same level of assurance as an air gap in situations involving raw sewage or highly contaminated sources. These alternative devices can still potentially fail under certain conditions, while the air gap remains a fail-safe measure due to its physical separation.