Which of the following items is NOT a cross-connection control?

Cross-connection controls are methods used to prevent contaminants from entering a potable water supply. They are essential for ensuring the safety and hygiene of drinking water systems. Among the options listed, floor drains do not serve as a method of controlling cross-connections.

A backflow preventer is specifically designed to stop the reverse flow of water, thereby preventing contamination of the water supply due to backpressure or back-siphonage. It is a critical component in cross-connection control. Similarly, a vacuum breaker allows air into the water system to prevent siphoning, which can also lead to contamination, making it a proper cross-connection control.

Air gaps provide a physical separation between the water supply and possible sources of contamination. This method is one of the most effective forms of cross-connection control because it removes any possibility of backflow.

Floor drains, while important for drainage and sanitation in food service areas, do not actively serve to protect the water supply from contamination caused by backflow or connections to non-potable sources, distinguishing them from true cross-connection control devices.