Red Seal Plumbing Practice Exam

Water heaters, hose bibs, and sill cocks are normally protected from backflow with:

1. A check valve

2. A vacuum breaker

3. An air gap

4. A pressure regulator

The correct answer is: A vacuum breaker

A check valve could prevent the backflow of water, but it does not provide protection against backflow caused by backsiphonage. It only allows water to flow in one direction. An air gap is a physical separation between the water supply and the outlet, but it is not always feasible or practical to have an air gap for every water outlet. A pressure regulator regulates the flow and pressure of water, but it does not prevent backflow. A vacuum breaker is the correct answer because it is specifically designed to prevent backflow caused by backpressure and back siphonage. It allows air to enter the system, breaking the vacuum that could potentially pull contaminated water back into the water supply.