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Backflow and Cross-Connection Prevention

Cross-Connection Control Program

This program is designed to minimize risk of contamination to the City’s public water system. Based on assessed hazard levels, an approved backflow prevention method or assembly may be required to be installed at the location identified by City of Vancouver Water Quality staff.

grassy area with sprinkler

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.

It takes everyone’s effort to protect the public drinking water system from contamination. The City’s Cross-Connection Control Program consists of municipal codes (VMC 14.04.110, VMC 14.04.140 and 14.04.155) and the City’s Cross-connection Control Procedures manual. Together, these outline the administrative and technical procedures the City of Vancouver implements to protect the public water system from contamination via cross-connections, as required by Washington Administrative Code (WAC) 246-290-490. For a copy of the City of Vancouver’s Manual, please contact the Water Quality group at

To better protect the City’s public water system, the City of Vancouver will start enforcing non-compliance actions for customers who do not comply with the City’s cross-connection control program requirements. The City of Vancouver gives ample notice to remind customers to schedule their backflow assembly test(s). If all passing backflow assembly test reports are not received by due date listed on the third notice, the City of Vancouver will assess a tiered fine structure based on the level of violation, per VMC 22.02.070. The City of Vancouver may terminate water service to the customer’s premises if the customer does not comply with the backflow assembly testing requirements of the final violation notice. 

The goal of the City of Vancouver is to provide clean, safe and reliable drinking water. We appreciate and thank all of our customers for assisting us in protecting our drinking water system from contamination. 

What is backflow?

Backflow is the undesirable reversal of flow of water or other substances, from the normal direction of flow in a piping system, through a cross-connection into the public water system or customer’s *potable water system. Backflow occurs due to a differential pressure existing between two different points within a continuous fluid system; a fluid of higher-pressure flows to a fluid of lower pressure. Backflow may occur due to either backsiphonage or backpressure. 

Backpressure occurs when the pressure in the piping downstream of the water meter or service connection is greater than the pressure provided by the City’s water system. This can be caused by a pump, elevated tank or piping, boiler, well or other means on the customer’s water system. 

Backsiphonage occurs when there is a reduction in water system pressure in the City’s water distribution system and/or consumer’s water system. This can be caused by a water main break or a large demand on the water distribution system by the Fire Department to put out a fire. 

*Potable water refers to drinking water that meets State requirements for delivering safe drinking water to customers. 

What is a backflow assembly?

A backflow assembly prevents water or other fluid substance from reversing during a backflow condition, protecting the potable water supply from contaminants. The backflow assembly is a mechanical device installed on water service lines (or at plumbing fixtures) to prevent backflow of contaminants into drinking water through cross-connections. 

What is a 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 public water system that could contaminant the potable water supply by backflow. This would include, but is not limited to, sewers, drains, conduits, pools, storage reservoirs, plumbing fixtures, or any other device. 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 cross-connections.

City and State requirements protect our community’s water supply

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 Vancouver Ordinance (VMC 14.04.140 and VMC 14.04.155). 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. 

The two state-approved backflow assemblies that follow are required to be installed per City of Vancouver standards, and must be tested by a Washington State certified tester upon installation and annually thereafter: 

  • Double Check Valve Assemblies (DCVA) 
  • Reduced Pressure Backflow Assemblies (RPBA) 

Atmospheric Vacuum Breakers (AVBs) are not an acceptable form of backflow protection. If you have an AVB and it breaks, leaks, or requires repairs, you will need to comply with our cross-connection control premise isolation program by installing a Washington State approved backflow assembly on your service line, directly behind your water meter. 

New in-ground sprinkler irrigation systems are required to have an approved lead-free backflow assembly installed on the service line, immediately downstream of the water meter. Visit the Standard Details section of this website for backflow assembly installation requirements. 

On-site water wells

If you have an on-site well and would like City of Vancouver water service, you must first comply to Washington state law (WAC 173-160 and WAC 246-290), and Vancouver Municipal Ordinance (VMC 14.04.140 and VMC 14.04.155), before the city can install water service. The following regulations must be met before water service begins: 

  • If you choose to keep your well: A Washington State approved lead-free reduced-pressure principal backflow assembly (RPBA) will need to be installed directly behind where the water meter will be installed, on the service line. The RPBA must be tested by a Washington State certified backflow assembly tester at the time of installation and annually thereafter, per Washington State Department of Health (WAC 246-290-490) and City of Vancouver Standards Specifications. This RPBA must be protected from freezing. 
  • If you choose to abandon your well: Use proper abandonment procedures, per Washington State Department of Ecology requirements (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 Washington State approved lead-free reduced-pressure principal backflow assembly as described above.

Additional questions about backflow and cross-connection prevention

Contact the Water Quality team by e-mail,, or phone at 360-487-8276

Backflow test reports submissions 

Certified backflow assembly testers have the option of entering their backflow assembly tests online or can submit backflow test reports directly to the City of Vancouver by e-mailing