What is the term for the valve used to connect a small-diameter service line to a water main?

The valve that is specifically designed to connect a small-diameter service line to a water main is referred to as a corporation stop. This type of valve is essential for controlling the flow of water from the main to the service line which supplies water to residential or commercial properties.

Corporation stops are typically installed directly into the water main and allow for easy access to turn the water supply on or off, making them vital for maintenance and repair operations. They are designed to handle pressures found in water distribution systems and ensure a reliable and secure connection between the main supply and service lines.

In contrast, the other options represent different types of valves that serve distinct functions. Ball valves are often used for isolating flow with a quick on/off action but are not specifically for connecting service lines. Inline valves are generally used in long runs of piping to control flow and may not specifically connect service lines to mains. Angle valves, while useful for changing the direction of flow, also do not serve the particular function of connecting service lines to water mains. Therefore, the corporation stop is the specialized valve that serves this crucial connection purpose in water distribution systems.