Cross Connection Practice Exam

What substance would discharge from the vent of a DCAPC subjected to backsiphonage?

1. Purified water

2. Carbonated water

3. Distilled water

4. Saltwater

The correct answer is: Carbonated water

In the context of a Double Check Valve Backflow Prevention Assembly (DCAPC) and backsiphonage, the correct answer is carbonated water. Backsiphonage occurs when there is a negative pressure in the water supply system, potentially causing non-potable substances to be drawn back into the potable water supply. Carbonated water is relevant because it represents a potential risk for contamination. If there is an interruption in water pressure—such as a burst pipe, water main break, or other situations that create backsiphonage—carbonated water, which might be stored or used in proximity to potable water systems, can unintentionally flow back into the drinking water supply. The other substances mentioned, while they may have distinct properties, do not adequately illustrate a typical backflow risk associated with backsiphonage in the same way that carbonated water does. The question revolves around the nature of potential contaminants that could be siphoned back into clean water, making carbonated water the most relevant choice.