A cross-connection is defined as any actual or potential physical connection between the public water system and any source that could contaminate the public water supply (i.e. plumbing fixtures, water utilizing equipment, or sprinkler systems). If improperly protected, contamination can result when a backflow event occurs; allowing contaminates to reverse flow from the fixture/equipment back into the customer’s water service and/or the public water system.
Cross-connections, or potential cross-connections, are required to have devices installed to protect the quality of the water in the distribution system. These devices, called Backflow Prevention Devices, are installed on irrigation systems, fire sprinklers or other types of water uses where water could become contaminated. For example, sprinkler systems are required to have backflow devices that are designed to prevent contaminants from entering the water supply. These backflow devices are installed on the domestic water service lines to protect against both back-siphonage and back-pressure. Once water enters your irrigation system it is no longer potable (drinking) water as it can become contaminated with lawn chemicals and bacteria. If a backflow device is not installed properly, or is not functioning properly, contaminated water from the sprinkler system can be forced back into your home’s water supply and/or the public water system. This can happen via pressure from the blow-out activity (back-pressure) or from a loss of pressure in the public water system (back-siphonage). Testing on sprinkler systems are performed each spring when the system is turned on.
To ensure that the water system is properly protected and that all system users receive safe drinking water, the District requires that all customers, residential, multifamily and commercial, test their backflow device(s) annually. After a backflow device is installed, initial testing is required to ensure proper function of the device and protection of the water system. Testing must be performed by a Washington State certified Backflow Assembly Tester and must be done at least once a year. If repairs are required, they usually can be completed at the time of the backflow test. After a successful test is completed, testers submit a test report to the District. The test reports are the District’s method of confirming that backflow assemblies have been maintained and function properly so the system is safe for all users.