Red Seal Plumbing Exam 2025 – 400 Free Practice Questions to Pass the Test

The other options are incorrect because a one inch water service to a building would most likely use a stop-and-drain valve as the shut-off valve. A ball valve may be used for smaller applications such as household plumbing, while a gate valve is typically used for larger water systems. A butterfly valve is usually used for regulating flow and is not ideal for a shut-off valve. However, a stop-and-drain valve allows for both stopping the flow of water and draining the system, making it the most suitable option for a building's main shut-off valve.