Backflow and Cross Connection Control
Keeping your drinking water safe is a two-way street. If you have a cross connection to the water system on your property, you must protect those connections with a Backflow Prevention Device.
What is a Cross Connection?
A cross connection is a point in a plumbing system where it is possible for a non-potable substance to come into contact with potable drinking water. For homeowners, these commonly include irrigation systems, boiler systems, radiant floor heat, private fire sprinkler systems, hot tubs, and pond equipment.
What is a Backflow?
Backflow occurs when water or other substances flow in the opposite direction than intended—such as the water in an irrigation system flowing back towards the source—allowing contaminants to enter your home's plumbing system and/or the public water system.
What Must You Do?
Washington State Administrative Code (WAC 246-290-490) requires customers to install, maintain, and test mechanical Backflow Prevention Devices to prevent these incidents from occurring. If you have any water-using systems described above, you need to:
Have a Backflow Prevention Device installed at the connection between your systems and our District's public water system;
Have a state certified Backflow Assembly Test performed annually (contact us to obtain a list of certified testers in our area); and
Send us a copy of your test result each year.