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1. What are "cross-connections" and "backflow"?

A "cross-connection" is any actual or potential physical connection between a public water system or the consumer's water system and any source of non-potable liquid solid, or gas that could contaminate the potable water supply by backflow. "Backflow" means the undesirable reversal of flow of water or other substances through a cross-connection into the public water system or consumer's potable water system. An Irrigation system is an example of a low hazard cross-connection. An example of a high hazard cross-connection would be a garden hose with the flowing end submerged in a container of pesticide. For more information please contact the Public Works Department at 425-831-4919.

2. 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.

3. What problems can result?

There are documented incidents in the United States where people have become sick because of contaminated water backflowing into potable systems. For more information please contact the Public Works Department at 425-831-4919.

4. Can cross-connections be avoided?

High hazard or unnecessary cross-connections are to be eliminated whenever possible. Unavoidable cross-connections (for example, fire sprinklers and irrigation systems) must be protected with a Backflow Prevention Assembly commensurate with the degree of hazard. For more information please contact the Public Works Department at 425-831-4919.

5. What is an "Approved Backflow Prevention Assembly"?

"Approved Backflow Prevention Assemblies" are commercially available double check valves that have been approved for the application by the City and are on the Washington State Department of Health pre-approved list. For more information please contact the Public Works Department at 425-831-4919.

6. Do I need a Backflow Prevention Assembly at my home?

Most residential units do not need a Backflow Assembly. However, if you have a fire sprinkler system or underground irrigation system, you must have a backflow prevention assembly on those systems. The Building and the Water Departments evaluate new buildings as to the degree of hazard and type of backflow protection required. For more information please contact the Public Works Department at 425-831-4919.

7. What if I have a Backflow Prevention Assembly?

Your must have the assembly tested annually by a state certified Backflow Assembly Tester (BAT) and a copy of the Test Report Form sent to the City of Snoqualmie Water Department. The City keeps a database of all backflow prevention assemblies in the system and when they were last tested and will attempt to notify property owners by letter when their assemblies are due to tested. Irrigation backflow assemblies are usually located in a plastic box or vault near the water meter. For more information please contact the Public Works Department at 425-831-4919.

8. How can I find a BAT to test my assembly?

For the convenience of City residents, the City maintains a list of testers. This is merely a list of companies who have submitted tests and certification information to our office. Many plumbing and irrigation contractors listed in the phone book can provide certified backflow assembly testing. For more information please contact the Public Works Department at 425-831-4919.

9. What regulations apply to Cross-Connection Control?

Cross-Connections are regulated by the Uniform Plumbing Code, WAC 246-290-490, and Snoqualmie Municipal Code 13.13. For more information please contact the Public Works Department at 425-831-4919.