What is the most common Backflow prevention device installed at a residential meter?

The most commonly installed backflow prevention device at a residential meter is the dual check valve. This device is utilized primarily in residential settings for its effectiveness in preventing backflow of non-hazardous substances into the potable water supply. The dual check valve consists of two independently acting check valves that work to prevent reverse flow. If one valve fails, the other provides an additional layer of protection, making it a reliable choice for safeguarding public health.

In residential applications, the dual check is often sufficient to prevent backflow because it effectively protects against potential issues without requiring the more complex and expensive devices suited for higher risk situations.

While options such as the air gap and reduced pressure zone (RPZ) devices offer superior protection and are used in more critical applications, they are typically not necessary for standard residential water systems. The double check valve, although alternative, is less common compared to the dual check in residential settings due to similar but often less-efficient performance.