Backflow / Cross Connection

The Woodinville Water District is committed to providing clean, safe drinking water to our customers. The District’s Backflow Prevention and Cross Connection Control program is required by Washington State code 246-290-490 and is designed to keep pollutants and contaminants from entering your clean drinking water system. A water system is a complexed connection of pipes that are connected to potential hazards like a fire system, irrigation system or other water using systems, these connection may require a backflow assembly to stop backflow and to prevent pollutants and contaminants from entering the drinking water system These assemblies need to be tested every year to ensure valves are working properly to stop backflow.

What is a cross connection?

A cross connection is a point in a plumbing system where the drinking water supply is connected to a non-potable source, like an irrigation system, fire system or other equipment. Pollutants or contaminants can enter the safe drinking water system through uncontrolled cross connections when a backflow occurs.

What is Backflow?

Backflow is the unwanted flow of non-potable substances back into the customer’s plumbing system and/or our public water system (i.e., drinking water). This backflow can occur when there’s a sudden difference in water pressure between the two systems during waterline breaks, repairs, or a water supply shut off.

Backflow preventers are mechanical devices designed to prevent backflow through these cross connections. However, for backflow preventers to protect as designed, they must meet stringent installation requirements and be inspected every year to ensure they’re working properly and preventing contamination from entering the drinking water.