Cross-Connection Control Program

Keeping Our Water Safe

Friday Harbor's Water Department has created this information to inform you of the potential threat of Cross-Connection (CC). The following information consists of the Town of Friday Harbor's adopted ordinances, Washington Administrative Code (WAC) 246-290-490, brochures on CC and common water terminology definitions.


One of the many threats to our drinking water supply is known as a Cross-Connection. A CC is the point at which a non-drinking water substance can possibly come in contact with drinking water. Connections as seemingly innocent as a sprinkler system, hot tub or ornamental pond can easily enable contaminants to enter potable (drinking) water lines via backflow. Customers install potential CCs like these and other water-using equipment every day, but, they are often unaware of the potential danger that lurks in the pipes as a result.


Backflow, caused by back-siphonage and/or back pressure, is the unwanted reverse flow of non-potable water back into a water system. Backflow can allow bacteria, chemicals or physical contaminants to enter the water system if CCs are uncontrolled.


The Water Department takes every precaution possible to prevent CC backflow from entering our distribution system. The Town's Cross-Connection Control (CCC) Program ensures that customers eliminate CCs whenever possible and control CCs that can't be eliminated by installing Department of Health (DOH) approved backflow preventers. To better protect public health, the Washington State DOH has revised the CCC regulations for public water systems. All systems are required to develop and implement CCC programs.

Additional Information

For more information about cross-connection please contact the Water Department at 360-378-8353.