Cross-Connection Control & Backflow

What is a Cross-Connection

The Washington Department of Healt describes a cross-connection as “any actual or potential physical connection between a drinking water system and any other non-potable substance (liquid, solid, or gas).” Simply, it is any connection between a consumer’s water system and a public water system that could potentially contaminate a potable water supply if an unexpected change in pressure occurs – a backflow. 

For more information about cross-connections please click this link

What is Backflow?

A Backflow occurs when water or other substances flow in the opposite direction (i.e. from a home to the public water system) allowing contaminants into the system. Backflow can occur when the public water system loses pressure like during a large mainline break. That change in pressure can draw non-potable water from the customer’s property from features like fire sprinkler systems, irrigation systems, hot tubs, etc. into the public water system at unprotected cross-connections. Prevention of backflow at cross-connections (“cross-connection control”) is vital to protecting public health.

What am I responsible for?

Washington State requires water systems and in turn, property owners to install and maintain backflow prevention assemblies WAC# 246-290-490 to protect the public water system. Blue Rock Water Company requires customers to have their backflow assemblies tested annually by a State Certified Tester.


About Backflow Assemblies

Washington State provides a list of acceptable backflow assemblies to fulfill the customer’s legal requirements to prevent contamination from entering the potable water supply. A complete list of devices are HERE.

As the backflow assembly is installed after the meter, each customer is responsible for costs related to installation, maintenance, testing, etc.

Where is a Backflow Assembly Required?

Blue Rock Water Company requires customers to install a backflow assembly whenever there is a possibility of a cross-connection between the public water system and a non-potable water source. Irrigation systems, boilers, hot tubs, pools and other water-using equipment are a non-exhaustive list of examples of cross-connections.

Find a Certified Backflow Assembly Tester (BAT)

Visit Washington Certification Services for a by county listing of certified Backflow Assembly Testers (BAT).


What if I Do Not Have my Backflow Assembly Tested?

Washington State law requires consumers to annually test their backflow assembly to ensure the proper function necessary to protect human health. Failure to comply increases the risk that non-potable water could contaminant the public water. Blue Rock Water Company will mail reminder notifications about backflow assembly testing requirements each year. It is the customer’s responsibility to have the backflow assemblies tested by the due date. If an assembly is not tested, Blue Rock Water Company  will take action, that may include disconnection of water service.

Blue Rock will work with customers to avoid disconnection; however, Blue Rock is responsible for protecting the public water and it will ultimately comply with those requirements. 

Completing a water use survey:

Uploading backflow inspection report: