Tennessee Wastewater Operator Practice Exam

What is the most effective method to prevent a cross connection?

1. Backflow preventer

2. Check valve

3. Air gap

4. Pressure relief valve

The correct answer is: Air gap

The most effective method to prevent a cross connection is the air gap. An air gap provides a physical separation between the potable water supply and any potentially contaminated source, effectively eliminating the potential for backflow. By maintaining this gap, the risk of contaminants entering the drinking water supply is significantly reduced. While other options, such as backflow preventers and check valves, provide some level of protection by preventing backflow under certain conditions, they can fail if not maintained properly or if subjected to conditions outside their design parameters. The air gap does not rely on mechanical components or moving parts, making it a more reliable option in preventing cross connections. In summary, the air gap is the best choice because it offers a straightforward and fail-safe method to keep clean water and potentially contaminated sources entirely separate.