Cross-Connection Control & Backflow Testing

Cross Connection Control Program

The Lake Whatcom Water and Sewer District, in its operation of four potable water systems (South Shore, North Shore – Eagleridge, North Shore – Agate Heights, and Johnson Well), is required to ensure protection of public health through the provision of minimum requirements and standards for design, construction, operation, and maintenance of its systems. It is essential that physical cross-connections, which create or have potential to create an imminent and substantial danger to public health, be eliminated from the distribution system and plumbing system of customers. Backflow can result in potable water systems becoming a transmitter of disease, toxic materials, and other hazardous liquids. Therefore, it is necessary to establish and maintain a Cross-Connection Control Program to protect the health of water customers by the control of actual and/or potential cross-connection through methods of containment and/or isolation.

The intent of this Program is to provide for the permanent abatement or control, by way of backflow prevention, of all cross-connections in the District’s systems, as required by WAC 246-290-490. When it is deemed necessary by the District’s Program Administrator, there will be installed, at a customer’s service connection, an approved backflow prevention assembly commensurate with the degree of health hazard to the water supply.

LWWSD Cross Connection Control Program 2019.04
Resolution 858

What is a Cross Connection?

A cross connection is any actual or potential physical connection between a potable (i.e., drinkable) water line and any pipe, vessel, or machine containing a non-potable fluid, solid, or gas where the non-potable substance can enter the potable water system by backflow. Garden hoses left connected and turned on when not in use can easily contaminate your home plumbing system. For questions or concerns about potential Cross Connections, please contact Lake Whatcom Water and Sewer District employee Rich Munson at (360) 737-9224 or email

Backflow Testing Requirement

Your residence has obligations regarding cross connections.  If your residence has an in-ground irrigation system, heat pump, boiler or any other type of identified cross connection that requires a backflow prevention device, you are required to have the device inspected annually by a State Certified Backflow Assembly Tester.

Remember: a cross connection not only threatens your health and safety, but that of your neighbors and the community as a whole, so please do your part to prevent them. For full information about Backflow Assembly testing, please see the Cross Connection Control Policy above.