The answer to 'what is shut-off valve' is a shut-off valve is a valve used to stop the flow of water or other fluids in a plumbing system. Shut-off valves are typically installed at the main water supply line to a home, as well as under sinks, behind toilets, and in other locations where it may be necessary to temporarily turn off the water. This allows homeowners to shut off the water supply to a specific fixture or area of the home for repairs or maintenance, without having to turn off the entire home's water supply.
Shut-off valves come in a variety of types, including gate valves, ball valves, and globe valves. They are usually made of brass, copper, or stainless steel, and can be either manually operated or automated. Proper maintenance and operation of shut-off valves is important to ensure they function correctly when needed.