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Find the main shut-off before you need it
The single most useful thing you can do is locate your main shutoff valve today, while water is calm, so you are not hunting for it ankle-deep in a flood. There are two places it lives. The interior main is where the water line enters the house: look on the wall facing the street, often near the water heater, in the basement, garage, a crawl space, or a utility closet. Follow the pipe from the meter side toward the house and the first valve you reach is usually it.
The exterior shut-off is at the water meter, typically in a box at ground level near the street or sidewalk. Lifting the meter-box lid, you will usually find the meter and a valve on the house side. Beyond that is the curb stop, the utility company valve, which often needs a special key and is meant for them, not you. For most shut-offs, the interior valve or the homeowner-side meter valve is the one you want.
Gate valve vs ball valve: how each one closes
Your main will be one of two types, and they close differently. A ball valve has a straight lever handle. Closing it is a single quarter turn: rotate the handle so it sits crosswise (perpendicular) to the pipe, and the water is off. Handle in line with the pipe means open; handle across the pipe means closed. These are reliable and fast, which is why they are the modern standard.
A gate valve has a round wheel handle, like a small spigot. You close it by turning the wheel clockwise (righty-tighty) and you may need several full turns until it stops firmly. Gate valves are common in older homes and have one weakness: if they have sat untouched for years, the internal gate can corrode and either seize or fail to seal fully. That is exactly why exercising the valve matters.
Exercise the valve so it works when it counts
A shut-off valve that has never been turned in fifteen years is the valve most likely to fail you, or to break off in your hand, during an emergency. Once or twice a year, fully close your main valve and reopen it. With a gate valve, after closing fully, back the wheel off a quarter turn from wide open so it does not bind. This keeps the mechanism working smoothly and tells you in advance whether the valve still seals.
If the valve will not budge, weeps, or will not fully stop the water when closed, do not force a corroded gate valve to the point of snapping it off, that turns a chore into a flood. Have it replaced on your schedule instead of discovering the problem mid-emergency. Our main water shut-off valve replacement cost guide covers what swapping an old gate valve for a modern quarter-turn ball valve runs, which is one of the better small upgrades for peace of mind.
Individual fixture stops and the emergency drill
You do not always need to kill the whole house. Most fixtures have their own local shut-off: small oval or lever stops under sinks and behind toilets, and a valve on the supply line to the water heater, washing machine and dishwasher. For a single leaking toilet or faucet, close that fixture stop (clockwise) and the rest of the house keeps water. Exercise these occasionally too, since they seize just like the main.
The emergency drill, worth walking once with everyone in the household: if a pipe bursts or a fixture floods, go straight to the main and shut it off, then open a low faucet (a basement or outdoor tap) to drain the pressure out of the lines. If the burst is from freezing, leave the faucet open and start thawing; our guides to frozen pipes and to what a burst pipe repair costs walk the next steps once the water is off. The whole point of knowing your valve cold is that those first 60 seconds decide how much of your house gets wet.
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