What is the first item used when installing a service line to a customer?

The corporation stop is the first item used when installing a service line to a customer because it serves as the connection point between the main water supply line and the service line that leads to the customer's property. This valve is typically installed by tapping into the main water line, allowing the utility to control the flow of water to the service line.

When the corporation stop is properly installed, it enables the water utility to shut off the water supply to the customer if necessary, making it crucial for maintenance and emergency situations. Following this step, additional components like the service valve, pressure gauge, and water meter can be installed, but without the corporation stop, the connection to the main water line cannot be successfully established.