What causes backflow?

Backpressure or backsiphonage can cause backflow through an unprotected cross-connection if the pressure in the potable system is lower than the pressure in the non-potable system. For more information please contact the Public Works Department at 425-831-4919.

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1. What are "cross-connections" and "backflow"?
2. What causes backflow?
3. What problems can result?
4. Can cross-connections be avoided?
5. What is an "Approved Backflow Prevention Assembly"?
6. Do I need a Backflow Prevention Assembly at my home?
7. What if I have a Backflow Prevention Assembly?
8. How can I find a BAT to test my assembly?
9. What regulations apply to Cross-Connection Control?