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Cross Connection Control

Cross Connection Control

Did you know that some common household systems can actually contaminate the water in your home? If it uses a cross connection, it has the potential to draw in water and other material from another source that may be contaminated. It can then spread the contamination to the public water system that connects to your home.

Examples of systems that use cross connections include:

  • Irrigation or in-ground sprinkler systems
  • Fire sprinkler systems
  • New or remodeled commercial or industrial buildings
  • Boilers
  • Swimming pools
  • Solar heat systems
  • Wash basins and service sinks
  • Auxiliary water supplies

If you have any of these in your home or business, you need backflow prevention. Properly installed and maintained backflow prevention assemblies stop contaminated water from reaching your tap or the water system.

For more details, see the following brochures:

Approved Backflow Prevention Devices

Most cross connections will need to have an approved mechanical backflow prevention device or assembly installed.

Types of approved backflow devices include:

  • Air gaps
  • Reduced pressure backflow assemblies
  • Double check valve assemblies
  • Pressure vacuum breaker assemblies
  • Atmospheric vacuum breakers

The type of assembly you choose will depend on the potential hazard present. In general, we accept air gaps and reduced pressure backflow assemblies for high hazards, and double check valve assemblies, pressure vacuum breaker assemblies and atmospheric vacuum breakers for low hazards.

The backflow preventer you choose must be listed on the Foundation for Cross-Connection Control and Hydraulic Research Approved Assemblies List. Assemblies not currently listed must have been listed at the time of your original installation.

We inspect assemblies upon installation and conduct periodic re-inspections on all existing assemblies. Assemblies must be tested annually by a state of Washington certified backflow assembly tester. Assemblies must also be tested after any repair or replacement. We require a copy of each test report.

Learn more about proper backflow prevention with these resources:

Cross Connection How To
Backflow Assembly Requirements
Cross Connection FAQ