What type of valve is used only when service is initiated or discontinued?

• A. Corporation stops
• B. Gate valve
• C. Ball valve
• D. Check valve

Answer: (A)

The valve used only when service is initiated or discontinued is the corporation stop. This small valve is installed on the service line where it taps from the main and is opened to start water service to a customer and closed to stop service. It’s specifically for shutting off or restoring service at the connection to the main, not for normal flow control on the distribution system. In contrast, gate or ball valves are used to isolate sections of the main or service lines during maintenance, and a check valve prevents backflow, so they aren’t intended for turning service on or off.