Locate the main shutoff with your home’s records, a local water utility’s guidance, or qualified help; then label its location and make sure every adult in the home knows where it is. Do not force a stuck or corroded valve.
Start with records and visible service areas
The main water shutoff location varies by home, climate, construction, and local utility design. It may be near a meter, an exterior service point, a basement, a utility room, a crawlspace entry, or another service area. Your closing documents, inspection report, water-utility materials, or a qualified plumber are better starting points than an internet diagram for a different home.
EPA WaterSense recommends knowing and checking water-using systems as part of home maintenance. Locate the shutoff before a leak, not while water is spreading.
Document rather than experiment
Once the correct valve is identified by a reliable source, take a photo, label it plainly, and record any instructions supplied by the utility or professional. Note what area it controls and whether there are separate appliance or fixture valves that should not be confused with the main shutoff.
If the valve is difficult to reach, corroded, leaking, unidentified, or requires tools you do not understand, do not force it. Ask a qualified plumber to identify it, assess its condition, and explain the appropriate operation for your home.
Keep the information usable
Put the location in the household emergency information, not only in a phone note. Review it after a move, remodel, water-service change, or plumbing work. If a leak is near electrical equipment or is large and uncontrolled, focus on personal safety and qualified emergency assistance rather than searching for the valve.