Which term describes a direct connection between a potable water system and an unregulated source that can introduce contaminants?

• A. Taste and odor problem
• B. Pressure loss
• C. Cross connection
• D. Disinfection break

Answer: (C)

Cross connection describes a direct link between a potable-water system and an unregulated source that can introduce contaminants. If such a connection exists, pressure changes or backflow can pull substances from the unregulated source into the drinking water, creating a serious contamination risk. This is exactly why cross-connection control is essential, using devices like air gaps or backflow preventers to stop contaminants from entering the distribution system. The other terms aren’t about a physical linkage to an unregulated source: taste and odor problems relate to quality factors in the water, pressure loss is a hydraulic condition, and a disinfection break is about losing residual disinfectant.