Which type of valve is found at the connection points between underground and distributor mains and may prevent water flow when damaged?

The shut-off valve is specifically designed to control the flow of water in a pipeline and is commonly located at critical junctions, such as between underground water mains and distributor lines. Its primary function is to enable or disable water flow in a system, particularly during maintenance or in case of emergencies.

In the context of the question, the shut-off valve would be essential at connection points because, if damaged, it can indeed prevent water from flowing. This property is crucial for isolating sections of the piping system for repairs or in the event of a leak or failure.

On the other hand, while other types of valves play critical roles in water systems, they have different functions. Check valves ensure that water flows only in one direction, preventing backflow, but they do not stop water flow entirely. Gate valves, while also capable of stopping flow, are typically used for on/off service and are more commonly found in locations where the valve won't be frequently adjusted. Pressure relief valves are safety devices designed to relieve excess pressure in a system but do not serve the same isolating purpose as shut-off valves.