Which type of valve is typically used to isolate water flow in plumbing systems?

The gate valve is commonly used to isolate water flow in plumbing systems because it provides a full flow path when open, minimizing pressure drop and allowing for maximum fluid flow. This design makes it ideal for applications where it's necessary to completely stop or allow water to flow through a pipeline.

Gate valves operate with a wedge mechanism that lifts a disk out of the flow path when opened, and they can be fully opened or closed, making them suitable for isolation purposes. The straightforward operation ensures that pressure and flow can be controlled effectively when needed.

In contrast, while ball valves are also used for isolation, they are more commonly preferred for quick shut-off rather than for throttling flow. Check valves are designed to prevent backflow and do not isolate flow. Meanwhile, butterfly valves, although useful in certain applications, are typically employed for regulating flow rather than complete isolation due to their design, which does not provide a full shut-off. Thus, for the specific purpose of isolating water flow, the gate valve is the most appropriate choice.