What is backflow?
Cross-Connection — also known as backflow — means any actual or potential physical connection between a public water system or the consumer’s water system and any source of non-potable water supply by backflow. This can include water from common sources including: Swimming pools, hot water heaters, and soda fountains.
How does backflow occur?
Backflow occurs when water pressure on the consumer’s side of the service connection is greater than the pressure provided by the public water system.
A drop in pressure, also known as back-siphonage, causes non-potable water to get sucked in to the public clean drinking water supply.
Although this is uncommon, the results can be deadly.
How do you prevent backflow / cross-connection contamination?
Backflow prevention assemblies protect the drinking water supply from becoming contaminated. These assemblies are tested annually to ensure they are in proper working order.
Through the Safe Drinking Water Act, a Cross Connection Control Program is required by the Washington State Department of Health and the Environmental Protection Agency to protect the public from contaminated water. This program calls for site inspections to identify and eliminate cross connections as well as annual testing of backflow prevention assemblies.
Legal Requirements for Water Customers / Property Owners / Testers
Annual Testing
Customers must obtain annual inspections and tests of their backflow assemblies. The City provides a Certified Backflow Testers List (PDF), which is updated every March. This list is a snap shot of credentials. Be sure to check that the tester you choose has current credentials and is using compliant test reports such as the form used by the City. Please view the Backflow Test Assembly Form (PDF).
Reference
BMC 18.07
Cross Connection Control Program Manual
Plumbing Changes and Backflow
Citizens’ Water Utility service provider (City or Utility District) is responsible for providing potable safe drinking water to customers’ service connections. Customer compliance is an essential component for the success of this mandated program. Prior to making plumbing changes obtain the proper permits (including new irrigation installation).