Operator terms · Water
What is a gate valve?
A gate valve is an on-off valve that opens or closes a water line by raising or lowering a flat gate across the pipe. Operators use gate valves to isolate a section of main for repair. They are meant to be fully open or fully closed, not to throttle flow.
Last reviewed 2026-08-03
What it is for
Distribution systems use gate valves to shut off a section of main so a break or a connection can be worked on without draining the whole system. More gate valves mean a smaller area has to be shut down for any one repair.
Open or closed, not partway
A gate valve is designed to be either fully open or fully closed. Leaving it part open wears the gate and does not control flow well, so operators use other valves when they need to throttle.
Common questions
- What does a gate valve do?
- It shuts off or opens a section of water main.
- Should a gate valve be left partly open?
- No; it is meant to be fully open or fully closed.
- Why space gate valves through a system?
- So a smaller area is shut down for any single repair.