Cross-connections exist in nearly every plumbing system. Identifying and evaluating each cross-connection is essential to determine the type of backflow protection required to safeguard the drinking water supply.
Some plumbing fixtures include built-in protection in the form of a physical air gap, which prevents contaminated water from flowing back into the system. However, many cross-connections require additional protection through the installation of an approved mechanical backflow prevention device or assembly.
Common cross-connections found in plumbing and water systems include:
• Wash basins and service sinks
• Hose bibs and exterior faucets
• Irrigation and sprinkler systems
• Auxiliary water supplies
• Swimming pools and hot tubs
• Photo developing equipment
• Solar heating systems
• Boilers
• Fire sprinkler systems
• Water recirculating systems
What is Cross-Connection?
A cross-connection occurs whenever the drinking water system is, or could be, connected to a non-potable source. This can include plumbing fixtures, equipment, or other systems that are not intended for drinking water use.
If a cross-connection is not properly controlled, backflow can occur, allowing pollutants or contaminants to enter the safe drinking water supply.
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.
