In a wet tap, how do operators contain the pressurized water?

• A. Flapper valve
• B. Gate valve
• C. Check valve
• D. Ball valve

Answer: (A)

In a wet tap, the goal is to prevent the live water in the main from blasting out as the tapping operation creates the connection. A flapper valve provides a fast, one-way seal at the tapping point, holding back the pressurized water until the service line is ready and the operator is prepared to allow flow. It’s specifically designed to contain pressure and prevent backflow during the tapping process, enabling a controlled connection.

Gate valves are meant for isolating flow and may not seal quickly or reliably enough under the dynamic conditions of a wet tap. Check valves prevent backflow in the downstream direction but are not intended to act as a pressure barrier at the tapping point itself. Ball valves are general shutoffs that don’t offer the same specialized containment function needed during wet tapping.