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. This type of valve allows fluid to flow in only one direction, effectively blocking any reverse flow that could occur due to pressure changes in the system. The mechanism within a check valve, often a swinging or sliding disc, automatically closes when fluid attempts to reverse direction, ensuring that contamination or other issues from backflow do not occur.

In contrast, ball valves, gate valves, and globe valves are primarily used for regulating flow rather than preventing backflow. Ball valves provide a quick shut-off and are commonly used for isolation purposes, while gate valves are typically utilized to start or stop the flow and are not designed to prevent backflow. Globe valves, on the other hand, are used for throttling and controlling flow, but they do not inherently offer backflow protection. Thus, the design and function of a check valve are specifically tailored for preventing backflow, making it the correct answer.