What is defined as a direct connection that can lead to contamination between potable water and non-potable water systems?

The term that describes a direct connection allowing potential contamination between potable (drinking) water and non-potable water systems is known as a cross-connection. A cross-connection occurs when there is a physical link between the clean water supply and any source of contamination, such as wastewater or industrial fluids. This connection poses a significant threat to public health because, in the event of a drop in water pressure, contaminated water can siphon back into the clean water supply, leading to waterborne diseases or exposure to harmful substances.

Understanding cross-connections is critical in plumbing and public health management, necessitating the implementation of proper safeguards like backflow preventers to maintain system integrity. Other options provided do not carry the same specific definition or recognition in plumbing and water safety standards, highlighting the unique and critical nature of the term "cross-connection" in preventing contamination.