What is the name of the valve that connects a customer's service line to the water main?

The valve that connects a customer's service line to the water main is known as a Corporation Stop. This valve is typically installed in the water main and serves as the point of connection for the service line that delivers water to a customer’s premises.

The Corporation Stop allows water utility personnel to control the flow of water into the service line, making it essential for both service connections and maintenance purposes. It enables the utility to isolate the service line for repairs or emergencies without disrupting the entire water main.

In contrast, the other valves listed serve different functions. The Backflow Preventer is designed to prevent contaminated water from flowing back into the potable water supply. A Shut-Off Valve, while used to stop the flow of water within a system, is typically found within a building or on a specific line rather than at the connection to the main. The Control Valve regulates the pressure or flow in a water distribution system but is not the connection point to a customer’s service line. Thus, the Corporation Stop is specifically intended for that pivotal connection, making it the correct answer.