What type of valve is used to allow water to flow in one direction while preventing backflow?

The check valve is specifically designed to allow fluid to flow in one direction while preventing backflow. This is crucial in plumbing systems to prevent contamination of the water supply and to maintain proper pressure. Check valves utilize a mechanism that automatically closes when the fluid attempts to reverse direction, sealing off the flow.

In contrast, globe valves are primarily used for regulating flow and do not inherently prevent backflow. Gate valves are mainly designed to start or stop the flow entirely; they do not provide a function for controlling flow direction. Ball valves are characterized by their ability to provide a quick shut-off but also do not prevent backflow. Therefore, the check valve is the singular option whose function directly aligns with the requirement to ensure one-way flow in a plumbing system.