Cross Connection Control and Backflow Prevention

The City of Enumclaw water system provides drinking water that is safe to drink and meets all State Department of Health and Federal health standards.

Cross Connections


One of the concerns of the Washington State Department of Health involves drinking water cross connections. A cross connection is any connection between a safe drinking water source and a unsafe source of water or liquid. This connection presents a health risk and needs to be eliminated or controlled.

Under certain conditions water can flow in the reverse direction as a result of pressure loss in the city’s delivery system. This is known as backflow. There are 2 types of backflow:
  • back-siphonage
  • back-pressure

Back-Siphonage


Back-siphonage is backflow caused by negative or reduced pressure in the supply lines that may be the result of a main break or firefighting activities in the area.

Back-Pressure


Back-pressure is caused when pressure in a non drinking water system is greater than the drinking water system pressure due to a pump, boiler, elevation difference or air or steam pressure.

Vacuum Breakers


There are mechanical devices that incorporate valves and springs to prevent backflow. They are known as backflow prevention assemblies or vacuum breakers. These are installed in the customers plumbing. The degree of backflow hazard dictates how many devices may be needed, what type and where they should be installed. The devices are required to be tested annually. At the bottom of the page are links to the city test form and to a website for use in searching for a certified tester.

Do's & Don'ts


Protect your water supply from contamination by taking the following precautions:
  • Do not submerge hoses in buckets, pools, tubs, sinks, ponds, etc.
  • Do not use spray attachments without a backflow prevention device.
  • Do not connect a waste pipe from a water softener or other treatment system to a sewer line or drain pipe, but maintain an “air gap” between the waste pipe outlet and the receiving drain
  • Do not use a hose connected to a drinking water source to unplug blocked toilets, sewer lines or drain pipes.
  • Do install a vacuum breaker device on all threaded hose bibs around your home or business. These devices are inexpensive and available at most hardware stores or improvement centers.
  • Do install an approved backflow prevention assembly on all underground lawn irrigation systems and closed-flow home fire protection lines. Please note that a plumbing permit is required for both of these systems when they are connected to your plumbing system.
Safe drinking water is a resource that all of us depend on. We need to be aware that system integrity is a community effort and responsibility. Please eliminate potential cross connections to ensure a healthy future for yourself, your family, and all members of the community.

Backflow Device Help


If you need help determining what type or where to install a backflow device, or the safety of your plumbing with regards to backflow, please contact the City of Enumclaw Cross Connection Control Specialist at 360-615-5728. You may also request a Water Usage Survey Questionnaire or an on-site survey at the same number.

Helpful Information