How to Shut Off Your Water in an Emergency

Every guide on this site eventually says the same thing: shut off the water. That instruction is worthless if you are learning where the valve is while water pours through your ceiling. Finding it takes five minutes on an ordinary afternoon and saves thousands of dollars once.

Go find it today. Then show everyone else in the household, and put a tag on it. A valve that only one person can find is a valve that fails you when that person is travelling.

The main shutoff sits where the water service enters the building, so start from the outside and work in. Look on the wall facing the street, at roughly the height the pipe enters.

• Basement homes: on the interior wall facing the street, often near the front foundation wall
• Crawlspace homes: just inside the crawlspace where the line comes through, sometimes in an access hatch
• Slab homes: in a utility closet, the garage, near the water heater, or occasionally outside in a wall box
• Apartments and condos: often a valve inside the unit for the unit's own supply, with the building riser controlled only by building staff
• Warm climates without basements: frequently outside, in a covered box near the hose bibb

There are two common valve types and they behave differently, which matters when you are in a hurry.

Old gate valves seize, and some fail the moment they are asked to work after twenty years of never moving. If yours will not close or will not seal, the fallback is the curb stop at your water meter, near the street in a covered box.

That valve usually needs a meter key, a long T-handled tool costing very little at a hardware store. A screwdriver and pliers can sometimes work in a pinch but often will not. If you have an older gate valve as your main, buying a meter key now is a reasonable precaution.

In an apartment or condo, you may have no access at all to the building riser. Know your building's emergency number before you need it; in a real emergency it is more useful than a plumber's.

Most fixtures have their own local shutoff, and using one is far less disruptive than killing water to the whole house. Toilets have a valve on the wall behind them. Sinks have valves under the cabinet, usually two. Water heaters have a valve on the cold inlet at the top.

These small valves seize even more reliably than main valves, because nobody ever turns them. Exercising each one once or twice a year is a genuinely worthwhile five-minute habit, and it tells you which ones have already failed at a moment when that is merely useful information rather than an emergency.