What does the term "cross-connection" mean in plumbing?

The term "cross-connection" specifically refers to an unprotected connection between a potable water supply and a non-potable source. This is a critical concept in plumbing because such connections pose a significant risk for contamination of drinking water. When there is a cross-connection, it is possible for harmful substances from the non-potable source to backflow into the clean drinking water supply, potentially leading to serious health hazards.

Understanding this definition is vital for plumbers and anyone working with water systems, as it underscores the importance of maintaining the integrity of potable water supplies. Cross-connections should be avoided or properly managed with backflow prevention devices to ensure public health and safety standards are upheld.