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Backflow Prevention

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Ventura River County Water District is committed to delivering safe, high quality water to its customers. The District operates 24 hours a day, 365 days a year, to ensure that the water delivered to our customers is kept free from harmful contaminants.

Ventura River County Water District has a backflow prevention program to protect the drinking water supply from pollution and contamination caused by cross-connections and backflow. When a water line is connected to equipment containing a non-potable substance, this is known as a cross-connection. Contamination may occur when water flows through a cross-connection from a non-potable source, such as a sprinkler system or heating and cooling system, into the potable water system. This can happen through a process known as backflow.

Due to our small staff Ventura River contracts with the County of Ventura Environmental Health Department to administer the Districts Backflow prevention program.
If you have questions regarding your backflow device or annual testing certifications contact Holly Sinclair, County of Ventura Environmental Health Department at 654-2436 or by email at


What is backflow?

When hydraulic conditions within system deviate from normal, the direction of the water flow can be reversed. This creates a backflow condition and the potential for contaminated water entering the distribution system.

How can backflow occur?

Backflow can occur two different ways, by backsiphonage and backpressure.

What is backsiphonage?

When there is a sudden reduction in the water pressure in the distribution system, such as during firefighting or when a water main breaks, water flow can be reversed. This can create a suction effect, drawing potential contaminates into the potable water distribution system.

What is backpressure?

Backpressure is created when pressure in a non-potable system, such as in a recirculating system containing soap, acid, or antifreeze, exceeds the pressure in the potable system providing the make-up water. This can force the potable water to reverse its direction of flow through the cross-connection between the two systems. Potential contaminates can then enter the potable water system.

How can backflow be prevented?

Ventura River recognizes four methods of backflow prevention:

  • Air Gap
  • Double Check Valve Assembly
  • Reduced Pressure Principal Assembly
  • Pressure Vacuum Breaker Assembly

The County of Ventura Environmental Health will determine which type of protection is required based on the degree of hazard that the property represents to the potable water supply.

What is a backflow prevention assembly?

A backflow prevention assembly is an approved, testable assembly which uses valves, in different configurations, to prevent potential contaminates from flowing into the potable water system.

Who is responsible for the testing and maintenance of the backflow prevention assembly?

It is the responsibility of the customer to ensure that the backflow prevention assembly is in proper operating condition at all times. Backflow prevention assemblies must be tested annually. Ventura County Environmental Health sends notices to customers reminding them when the annual test is due. The customer must contact an approved certified tester to perform the test. If any repair work or maintenance is performed on the assembly, a certified tester must retest the assembly immediately and submit the test results to the County of Ventura.