Cross Connections

One of the concerns of the Washington State Department of Health involves drinking water cross connections. A cross connection is any connection between a safe drinking water source and an unsafe source of water or liquid. This connection presents a health risk and needs to be eliminated or controlled.

Under certain conditions, the water can flow in the reverse direction as a result of system pressure loss. This is known as backflow. There are two types of backflow: Backsiphonage and Backpressure.

Backsiphonage is backflow caused by negative or reduced pressure in the supply lines that may be the result of a main break or firefighting activities in the area.

Backpressure is caused when a non drinking water system pressure is greater than the drinking water system due to a pump, boiler, elevation difference, or air or steam pressure.

Safe drinking water is a resource that all of us depend on. We need to be aware that system integrity is a community effort and responsibility. Please eliminate potential cross connections to ensure a healthy future for yourself, your family, and all members of the community.

Check out the Certified Backflow Prevention Assembly Tester List put together by City of DuPont Water Quality. 

Needing to submit your backflow testing information? This is a free service to backflow vendors. Click here to access our portal and submit your information. 


Backflow Assembly Inspection Line - Email Backflow@dupontwa.gov or call at (253) 964-8121, extension 5407.