Which backflow prevention devices are approved for use at service connections?

Backflow prevention devices are essential in ensuring that no contaminated water flows back into the potable water supply. Each of the devices mentioned plays a vital role in providing reliable protection at service connections, which are points where water is supplied to consumers.

An air gap separation is a physical distance between the water outlet and the flood level of a fixture, which effectively prevents backflow by creating a gap that cannot be crossed. This is one of the most effective forms of backflow prevention because it does not rely on mechanical parts that can fail.

The double check valve is composed of two check valves arranged in series. It allows water to flow in one direction while preventing backflow. It is commonly used in low-risk applications where the potential for contamination is considered moderate.

The reduced pressure principle device is more sophisticated and is used in higher hazard situations. It consists of two check valves with a pressure relief valve between them that maintains a lower pressure in the chamber, ensuring that water will flow in one direction under both backpressure and backsiphonage conditions.

All of these devices—air gap separation, double check valves, and reduced pressure principle devices—are approved for use at service connections, making the answer to this question comprehensive in acknowledging the effectiveness of these various methods in maintaining