Cross Connection Practice Exam

Which component is essential for maintaining a backflow preventer’s functionality?

1. Regulator

2. Check valve

3. Strainer

4. Flow controller

The correct answer is: Check valve

The essential component for maintaining a backflow preventer's functionality is the check valve. A check valve is a crucial part of the backflow prevention system because it allows fluid to flow in only one direction, preventing backflow, which occurs when the flow of water unexpectedly reverses. This is vital in protecting the potable water supply from contamination by non-potable sources. When a backflow preventer is installed, it primarily uses the check valve to stop water from returning to the supply line. If the pressure in the downstream system drops below the pressure of the water in the supply line, the check valve closes, providing a barrier against potential contamination. The other components mentioned, like regulators, strainers, and flow controllers, play different roles within water systems but do not serve as the main line of defense against backflow. Regulators manage pressure levels, strainers filter out debris from the water supply, and flow controllers regulate the amount of water flowing through a system. While these components are important for overall water quality and system efficiency, they do not specifically maintain the essential function of preventing backflow like the check valve does.