A cross connection is any actual or potential connection between the drinking water lines and potential sources of pollution or contamination such as a piping arrangement or equipment that allows the drinking water to come in contact with non-potable liquids, solids, or gases hazardous to humans in the event of a ...

The purpose of the cross-connection control program is to reduce the hazard of contamination of the public water system by identifying actual and potential cross-connections and taking action to protect the system from these hazards.

The best method of preventing backflow is an air gap which either eliminates a cross- connection or provides a barrier to backflow. If an air gap is not practical, a mechanical backflow preventer, which provides a physical barrier to backflow, is the next best approved method.

This helps ensure contamination cannot enter the system through points of connection or leaks. Though difficult to detect, water pressure can sometimes be disrupted causing water to accidentally flow backwards. This can result in siphoning of unknown materials into the drinking water.

(e) "Cross-Connection" is an unprotected actual or potential connection between a potable water system used to supply water for drinking purposes and any source or system containing unapproved water or a substance that is not or cannot be approved as safe, wholesome, and potable.

The degree of hazard is a commonly used phrase utilized in cross connection programs and is simply a determination on whether the substance in the non-potable system is toxic (health hazard) or non-toxic (non-health hazard). There are three degrees of hazard; severe, moderate and minor.