What is the primary role of a check valve in backflow prevention?

The primary role of a check valve in backflow prevention is to allow forward flow only. Check valves are designed to permit the flow of water in one direction while preventing any reverse flow, which is essential in maintaining the integrity of a water supply system. This function is crucial in backflow prevention because reverse flow can lead to contamination of the potable water supply.

In systems where backflow may occur, check valves act as a first line of defense against the unintended movement of water, preventing contaminated water from entering clean water lines. Their construction typically includes a movable element, such as a disc or ball, that opens when water flows in the intended direction and closes when there is a reversal in flow, effectively sealing off the system.

Understanding the specific function of check valves helps to highlight their importance in maintaining water quality and protecting public health.