What does the term "cross connection" refer to in water systems?

The term "cross connection" refers specifically to a physical link between potable (drinking) water and another source that may contaminate it. This is a critical concept in water systems because cross connections can jeopardize the safety of the drinking water supply. For example, if there is a physical connection between a clean water source and a source of contamination (like irrigation systems, industrial processes, or even non-potable water supplies), there is a risk that contaminants can flow back into the potable water supply, particularly during changes in pressure in the system.

The understanding of cross connections is vital for water system operators to ensure that proper backflow prevention devices are installed to protect the integrity of drinking water. Ensuring no cross connections exist helps maintain public health by preventing the potential for waterborne diseases and pollutants from entering the potable water supply.