What does a physical cross-connection allow?

A physical cross-connection permits a flow of water into an approved potable water supply from an unapproved supply. This scenario is critical in discussions of water safety and public health. A cross-connection can occur when there's a direct link between the potable water system and a non-potable source, such as irrigation systems, sewage systems, or industrial lines.

When such a connection is made, it poses a significant health risk because contaminants from the unapproved source can backflow into the clean water supply due to changes in pressure or other factors. This backflow can introduce harmful substances into the drinking water, potentially leading to waterborne illnesses and other health hazards.

Recognizing and preventing physical cross-connections is a fundamental concern in sanitation and public health practices, as it ensures the integrity of potable water systems and protects community health. Proper plumbing codes and guidelines are established to prevent these situations and maintain safe drinking water.