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What is Cross-Connection?

Cross-connections exist whenever the drinking water system is or could be connected to any non-potable source (plumbing fixture or equipment used in any plumbing system).  Pollutants or contaminants can enter the safe drinking water system through uncontrolled cross-connection when backflow occurs.

Where are Cross-Connections Found?

Cross-connections are found in all plumbing systems. It is important that each cross-connection be identified and evaluated as to the type of back-flow protection required to protect the drinking water supply. Some plumbing fixtures have built-in back-flow protection in the form of a physical air gap. However, most cross connections will need to be controlled through the installation of an approved mechanical back-flow prevention device or assembly. Some common cross-connections found in plumbing and water systems include:

-Wash basins & service sinks

-Hose bibs

-Irrigation sprinkler systems

-Auxiliary water supplies

-Swimming pools/hot tubs

-Photo developing equipment

-Solar heat systems


-Fire sprinkler systems

-Water re-circulating systems

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