What type of valve is commonly used for shutting off water supply in a plumbing system?

A ball valve is commonly used for shutting off the water supply in a plumbing system due to its effectiveness in providing a tight seal when closed. The design features a spherical closure element (the ball) that has a hole through its center, allowing water to flow when the valve is in the open position. When closed, the ball's solid surface blocks the flow, ensuring there are minimal leaks.

This type of valve is favored in residential applications for its ease of operation, requiring only a quarter turn to fully open or close. Additionally, ball valves are durable and perform well under high pressure, making them suitable for a variety of plumbing configurations.

In contrast, other types of valves have different functions or are not as efficient for outright shut-off purposes. For instance, a gate valve is typically used where minimal pressure drop is desired during flow and isn’t as reliable for tight sealing over time. A butterfly valve is more commonly employed in larger pipelines where space is limited, and a check valve allows flow in one direction only, preventing backflow, but does not serve to shut off water supply.