What device is used to prevent backflow in an RV's water system?

The device used to prevent backflow in an RV's water system is a vacuum breaker. A vacuum breaker is specifically designed to protect potable water supplies from contamination due to backflow. It works by allowing air to enter the system when a negative pressure develops, which prevents water from being siphoned back into the clean water supply. This is essential in maintaining the integrity of the water system, especially where there is a risk of contaminants being drawn back through the system.

In contrast, while pressure regulators, flow restrictors, and check valves serve important functions in water systems, they do not specifically address the risk of backflow in the same manner. Pressure regulators control the water pressure entering the system, which helps protect fixtures and prevent leaks, while flow restrictors are designed to limit the flow of water to conserve water usage and control pressure but do not prevent backflow. Check valves allow fluid to flow in one direction but do not inherently provide a mechanism to break a vacuum or prevent siphoning, which is the primary role of a vacuum breaker.