Frequently Asked Questions

A link between your drinking water system and a source of contamination, a way for "bad stuff" to get into your good clean drinking water.

The term cross connection means any actual or potential connection (piping/hose) between a public water system and a source of contamination.

Did you know that water can flow two directions in a hose or pipe? When water is flowing in the opposite direction from its normal flow that is backflow and it can put our drinking water in danger.

• Commercial:
  • Boiler
  • Carbonation Equipment
  • Dental Equipment
  • Etching Tanks
  • Film Processors
  • Fire Systems
  • X-Ray Machines
• Residential:
  • Auxiliary Water Supply (Wells)
  • Boiler
  • Fire Sprinkler System
  • Hose Bibs/Garden Hose
  • Hot Tubs/Spas
  • Lawn Irrigation Systems
  • Swimming Pools

Note: Toilets and sinks have an air gap for backflow protection.

All it takes for backflow conditions to occur is a drop in line pressure in the water main, which can happen due to use of hydrants for fire fighting, water main break, high usage or backpressure. In America, we all assume when we turn the tap on that we have safe drinking water. This is a luxury we enjoy, but not without very strong regulations and considerable expense. Our drinking water is among the safest in the world. Water protection and conservation requires the effort and cooperation of everyone.

The Safe Drinking Water Act of 1986, and Washington State Administrative Code (WAC 246-290-490) requires the Water District to administer a Cross Connection Control Program that will protect the drinking water supply, and to coordinate with the Local Authorities that protect the drinking water supply from possible backflow hazards within the plumbing system of buildings.

If you have questions pertaining to your home or building contact the Woodinville Water District’s Water Quality Specialist at 425-487-4125 or by email.

Legally, the "purveyor" of the water supply is responsible for the water quality and for implementing and maintaining a cross connection control program in order to prevent the contamination of the public water system. The water purveyor is the public water department, up to and including the service connection from the water main. From the outlet of the water meter or service connection including all piping down downstream inside the owner’s premise, the legal purveyor of the water supply is actually the property owner.

• An Approved Air Gap Separation
• Mechanical Assemblies used in the prevention of backflow are separated into three types:
  • Double Check Valve Assemblies (DCVA), including Double Check Detector Check (DCDA)
  • Pressure Vacuum Breaker Assemblies (PVBA) and Spill-Resistant Pressure Breaker Assemblies (SVBA)
  • Reduced Pressure Backflow Assemblies (RPBA) including Reduced Pressure Detector Assemblies (RPDA)
• Mechanical Devices used in the prevention of backflow include:
  • Dual Check Backflow Preventer
  • Dual Check with Atmospheric Vent, also known as a Backflow Preventer with Intermediate vent
  • Hose Bib Vacuum Breaker device (HBVB), also known as a Hose Connection Vacuum Breaker
  • Residential Meter Check
  • Atmospheric Vacuum Breaker (AVB)

Backflow assemblies must be tested at the time of installation, annually after installation, after a backflow incident, and after any repairs have been made. If an assembly is relocated and/or reinstalled it must be retested. Anytime a backflow assembly is tested a test report needs to be submitted to Woodinville Water District.

To test backflow assemblies in the State of Washington a person must have a Washington State Department of Health Certification as a Backflow Assembly Tester (BAT).

If your backflow assembly fails it annual test; it needs to be cleaned, repaired or in some cases it may need to be completely replaced. After cleaning, repair or replacement a successful re-test performed.