Cross Connection Controls

Keeping Our Water Safe

What do you think the chances are that you have a connection to Highline Water District's distribution system that could threaten public safety? Although you most likely don't THINK your connection could be dangerous, it's possible that it is.

One of the many threats to our drinking water supply is known as a cross-connection (CC). 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 backsiphonage and/or backpressure, 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.

Highline Water District takes every precaution possible to prevent CC backflow from entering our distribution system. The District'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.

"Cross-connection controls programs are an integral part of effective water system operations and are based on sound public health principles. We are committed to protecting the health of the people in Washington State by ensuring safe and reliable drinking water," said Terri Notestine, Washington State Department of Health. "Cross-connection control programs are part of a multiple barrier system that helps protect the drinking water."

When a potential CC problem exists, Highline Water District conducts a hazard survey. We evaluate each premise for CC hazards and ensure that an appropriate DOH-approved backflow preventer is installed if needed. Some water-using equipment has built-in backflow protection in the form of a physical air gap. But, if CC hazards are present, customers may be required to install a backflow preventer at the meter to "control" the CC and protect the public water system.

These efforts will protect the public water system, but to protect the health of building occupants, customers should consult their city building department for assistance with CCC. City building depts. enforce the CCC requirements of the Uniform Building Code.

When should I be concerned about CCs? Anytime you modify the plumbing and/or install a new plumbing fixture or water-using equipment, or if you ever notice an unusual color, taste or smell from your water, you should contact us and schedule a CCC survey.

For more information about cross-connections, contact Jon Seibel, Operations Supervisor at (206) 592-8946 or, you can find more information online from Washington State DOH at

Cross Connection Examples
  • Wash basins and service sinks
  • Hose bibbs
  • Irrigation sprinkler systems
  • Auxiliary water supplies
  • Laboratory & aspirator equipment
  • Photo developing equipment
  • Processing tanks
  • Boilers
  • Water recirculating systems
  • Swimming pools
  • Solar heat systems
  • Fire sprinkler systems
Contact Us

Highline Water District
23828 30th Ave. S.
Kent, WA 98032
Phone: 206-824-0375
Emergency: 206-824-0375
FAX: 206-824-0806
Hours: M-F 7:00-4:00

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