What defines a cross connection in plumbing?

A cross connection in plumbing is characterized as a connection between a potable (drinking) water system and a contaminated water system, which can lead to the contamination of the potable water. This definition is critical in plumbing design and water safety, as it emphasizes how backflow can occur when there is a change in pressure, allowing non-potable water or pollutants to enter the drinking water supply.

Understanding cross connections is essential for preventing health hazards related to waterborne diseases and ensuring the safety of public water supplies. Proper plumbing design includes measures such as backflow prevention devices to mitigate the risks associated with cross connections.

The other options do not accurately represent the definition of a cross connection. A high-pressure water pipe does not inherently connect potable and non-potable water systems. Similarly, a connection between two potable systems is not a cross connection, as this would not pose a contamination risk. Lastly, a sealed plumbing fitting, although an important plumbing component, does not define a cross connection in the context of water supply and safety.