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
-Boilers
-Fire sprinkler systems
-Water re-circulating systems
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?
Backflow Preventer Assembly Example
Example of how a backflow preventer works
Both types of backflow preventors are used to prevent backflow of contaminated water into the potable water system:
Reduced-Pressure Backflow Assembly (RPBA) - used for High-risk scenarios and is normally placed above ground and in a building.
Dual-Check Valve Assembly (DCVA) used for LOW-risk scenarios and is normally berried, only exposing the top. The standard location is near the water meter in a separate box. However, can be located near irrigation controls.
