What is a backflow preventer?

A backflow preventer is a means or mechanism to prevent backflow. The basic means is an air gap, which either eliminates a cross-connection or provides a barrier to backflow. The basic mechanism is a mechanical backflow preventer, which provides a physical barrier to backflow. The principal types of mechanical backflow preventers are the reduced-pressure principle assembly, the pressure vacuum breaker assembly, and the double check valve assembly. A secondary type of mechanical backflow preventer is the residential dual check valve.

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1. What is a cross-connection?
2. What is backflow?
3. What is backpressure backflow?
4. What is backsiphonage?
5. Why do water suppliers need to control cross-connections and protect their public water systems against backflow?
6. What should water suppliers do to control cross-connections and protect their public water systems against backflow?
7. What is a backflow preventer?
8. What is an air gap?
9. What is a reduced principle assembly (RP)?
10. What is a double check valve assembly (DC)?
11. What is a residential dual check valve (RDC)?
12. Why do backflow preventers have to be tested periodically?
13. Where can I get more information about cross-connection control?