What type of valve is typically used to prevent backflow in plumbing systems?

A check valve is specifically designed to prevent backflow in plumbing systems by allowing fluid to flow in only one direction. This function is crucial in maintaining the integrity of the plumbing system, as it stops potentially contaminated water from flowing back into the clean water supply.

Check valves typically consist of a movable disc or gate that seals against a seat when the flow reverses, effectively blocking the backward flow of water. This essential feature makes them vital in scenarios such as sewage systems, irrigation systems, and any applications where backflow could cause contamination or damage.

Other types of valves, such as butterfly valves, gate valves, and ball valves, serve different purposes. Butterfly and ball valves primarily regulate flow but are not specifically designed to prevent backflow. Gate valves also allow for flow regulation but can potentially allow backflow if there is a change in pressure. Therefore, the check valve stands out as the appropriate choice for backflow prevention.