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Find your home’s main shutoff before water starts causing damage.
A whole-house water shutoff valve isolates your plumbing from the incoming supply. Closing it can stop new water from feeding a leak, but water already in pipes may still drain.
Look near where the water service enters the home: common spots include a basement, crawlspace, utility room, garage, or exterior foundation wall. Locations vary by home and climate.
A ball valve usually has a lever that aligns with the pipe when open and sits across it when closed. A gate valve has a round wheel and may seize or fail internally as it ages.
Turn a ball-valve lever a quarter-turn, usually until it is perpendicular to the pipe. Gate valves close by turning the wheel; never force a stiff handle, which may be damaged or stuck.
Automatic shutoff systems use a motorized valve and either monitor flow through the main line or rely on separate sensors near leak risks. A trigger can close the valve and send an alert.
Match detection to your home’s risks. Flow monitoring with dedicated sensors can cover more areas, while a sensor near one appliance may help with that risk but will not monitor the whole home.
A licensed plumber should handle work that cuts pipe, joins pressurized lines, or changes a service connection. Local permit rules vary, and pipe material and pressure affect the installation.
Keep the valve accessible, with room to operate and service it. Outdoor replacement needs extra caution; a plumber can check compatibility, orientation, pressure conditions, and local requirements.
Protect people first. Close a nearby fixture valve if safe, or use the homeowner-operated main shutoff if water continues or the source is unclear. Stay clear of standing water near electrical equipment.
A working main valve can stop new water entering through the service line, but water already in plumbing may still escape. Read the full guide for locating, operating, and choosing a shutoff.
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