These devices, typically located behind the washing machine and connected to the water supply lines, control the flow of both hot and cold water to the appliance. They consist of a small handle or lever that, when turned clockwise, closes the valve and stops the water flow, and when turned counter-clockwise, opens the valve and allows water to flow. Common types include ball valves, gate valves, and stop-and-waste valves.
Restricting water flow to the appliance when not in use mitigates the risk of leaks and potential water damage. This control is particularly crucial during maintenance, repairs, or when the appliance is left unattended for extended periods. Historically, simple screw-type valves were common, but modern designs offer improved reliability and ease of operation. Their widespread adoption reflects a heightened awareness of water conservation and home safety.