Define cross-connection control and backflow prevention in drinking water systems.

• A. Techniques and devices that prevent contaminated water from flowing back into the clean supply line, protecting public health
• B. Methods for connecting multiple water sources for redundancy
• C. Procedures for testing water chemistry
• D. Systems that increase water pressure in distribution networks

Answer: (A)

Cross-connection control and backflow prevention focus on stopping reverse flow from a potentially contaminated source into the drinking-water system. A cross-connection is any physical link between the potable water supply and a non-potable source that could introduce contaminants. Backflow prevention uses devices and methods—like air gaps and backflow preventers—to block water from flowing backward when pressure changes in the system. By keeping reverse flow from occurring, these controls protect public health and maintain the integrity of the clean water supply. The other options describe linking sources for redundancy, testing water chemistry, or increasing pressure, none of which address preventing backflow or suppressing cross-connections.