Backflow & Cross-Connection Prevention

If you are a property owner with an in-ground sprinkler system or private well, state and local laws require that you install and maintain a backflow prevention device on your service line and have it inspected yearly by a certified tester.

BackflowBackflow Diagram

Backflow is a flow in reverse from the normal direction of flow in a piping system. It occurs due to a differential pressure existing between two different points within a continuous fluid system; a fluid of higher pressures flowing to a fluid of lower pressure. Backflow may occur due to either "backsiphonage" or "backpressure."

Cross Connection

A cross connection is any actual or potential physical connection between a "potable water" line and any pipe, vessel, or machine containing a non-potable fluid, solid or gas, allowing possible entry to the water system by backflow. The non-potable or unapproved water supply system may contain contaminated liquids, solids, or gases, of unknown or unsafe quality. Bypass arrangements such as jumper connections, removable sections, swivel or changeover devices are considered to be a cross connection.This would include, but is not limited to:

  • Conduits
  • Drains
  • Plumbing fixtures
  • Pools
  • Sewers
  • Storage reservoirs

Irrigation Systems

If you have or are planning on installing an irrigation system, you must first comply with Washington State Law (WAC 246-290), and City of Washougal Ordinance (13.40). These laws require that all irrigation systems have approved backflow protection. A plumbing permit is also required when installing an irrigation system. Without proper backflow protection, your irrigation system could endanger the health of your family, neighbors, and others in the community who are using the public water system.

Termination of Water Service

Improper installation of a state-approved backflow prevention device or failure to meet testing requirements are grounds for termination of water service. The three state-approved backflow assemblies that follow are required to be installed per City of Washougal standards, and must be tested by a Washington certified tester upon installation and yearly thereafter:

  • Double Check Detector Assemblies (DCDA)
  • Double Check Valve Assemblies (DCVA)
  • Pressure Vacuum Breaker Assemblies (PVBA)
  • Reduced Pressure Backflow Assemblies (RPBA)

Atmospheric Vacuum Breaker

The atmospheric vacuum breaker (AVB) is the only backflow prevention device that does not require annual testing.  New installations of these devices are no longer accepted in the City of Washougal Water service area. If your AVB is damaged or non-functional you will be required to obtain a plumbing permit and install a double check valve assembly (DCVA) to remain in compliance.

On-Site Water Wells

If you have an on-site well and would like City of Washougal water service, you must first comply with Washington state law (WAC 173-160 and WAC 246-290), and Washougal Municipal Ordinance (13.40), before the city can install water service. Failure to comply with state and local regulations are grounds for termination of the water service. The following regulations must be met before water service begins:

  • If you choose to keep your well: Installation and testing of a state-approved reduced-pressure backflow assembly (RPBA), per City of Washougal Standards Specifications. This backflow prevention device must be protected from freezing.
  • If you choose to abandon your well: Proper abandonment procedures, per Washington state law WAC 173-160, using a licensed well driller. Capping the well or pulling the pump is not proper abandonment and will require installation of a state-approved reduced-pressure backflow assembly device.

Contact Us

If you have any questions concerning backflow installations, certified testers, or approved backflow prevention device please contact the Water Department by phone at 360-835-2662, or email Travis Davis or email Ryan Baker.

Backflow Reports

Customers and testers can submit backflow test reports directly to the City by email.

Testers with City of Washougal credentials can directly enter the test reports into our electronic system here:  

For assistance with electronic entry: Tokay SQL Web Test Users Guide

Backflow Information