When water is coming from somewhere it should not be — a burst pipe, a fitting that let go, a supply line under the sink spraying — the one thing that stops the damage is knowing where to turn the water off. Not later, not after you find a video: right then. Every minute the water runs is more floor, more drywall, and more of the ceiling below it.
The best time to find your main shutoff is a calm afternoon when nothing is wrong. That way, the day something is wrong, you already know exactly where to go and that the valve actually works. This guide covers the two kinds of shutoff in a typical home, where the main valve usually hides, how to turn it off without breaking it, and the few situations that are a call to a pro or the water utility rather than a thing to force.
The two shutoffs — local and main
- Local fixture valves — small valves right at a fixture: under a sink on each supply line, behind or below the toilet, and on the pipes feeding the water heater and the washing machine. Use one of these when the leak is at a single fixture and you can reach its valve. It leaves the rest of the house with water.
- The main shutoff — one valve that stops water to the whole house. Use it when the leak is a pipe rather than a fixture, when you cannot find or reach a local valve, or when water is coming faster than you can think. It is the one every adult in the house should be able to find in the dark.
Where the main shutoff usually is
Follow the water. The main valve is almost always on the pipe where the water supply first enters the house, close to the front or the street-facing side, within a few feet of where it comes through the wall or floor.
Where to look, by house type
- In a basement or crawlspace — on the wall that faces the street, often near the front and low down, where the supply line comes through.
- On a slab in a warm climate — frequently in the garage, near the water heater, or just inside an exterior wall on the street side.
- Near the water heater or the laundry — the main line often runs to those first, so the shutoff can be close by.
- At the meter, outside — there is usually a valve in or beside the meter box near the street or sidewalk. That one often needs a special meter key to turn, and the valve on the street side of the meter typically belongs to the water utility, not you. Use the inside main first if you have one.
Know which handle you have
Look for one of two handles. A lever you turn a quarter turn is a ball valve — the modern kind, quick and reliable. A round wheel you turn several times is a gate valve — common in older homes, and the kind most likely to seize with age. Knowing which one you have tells you how it closes and how gently to treat it.
Turn it off — and test it before you ever need it
- Ball valve (lever) — turn the lever a quarter turn so it sits crosswise to the pipe. When the handle lines up with the pipe the water is on; when it sits across the pipe the water is off.
- Gate valve (round wheel) — turn it clockwise, and expect several full turns to close it. Turn it gently. Old gate valves corrode inside and can snap or crumble if you crank on them, which turns a stuck valve into a bigger emergency.
Do not wait for a flood to find out the valve works. On a calm day, close the main, then open a faucet somewhere in the house. The flow should drop to nothing within a few seconds. Turn the main back on, and the faucet should run normally again. If the valve will not turn, will not fully stop the water, or drips afterward, that is a repair to book now, while the water is calm — not something to discover with a pipe open.
While you are there, make sure everyone in the household knows where the valve is and which way it closes. In a real leak, the person nearest the valve is not always the one who knows plumbing.
When it is shut-off-and-call, not fix-it-yourself
- Water near electrical — if water is spreading toward outlets, the panel, light fixtures, or an appliance, cut power to that area at the breaker as well as shutting the water. If you cannot reach the breaker without standing in water, do not — leave and call an electrician or the fire department from outside.
- A valve that will not budge — if the main is seized, do not force it until it breaks. Shut off at a local valve if you can, or call the water utility, who can close the water at the street.
- The meter or street-side valve — the valve on the utility's side of the meter is theirs to operate, and it often needs a special key. If the inside main fails and you have to reach the street valve, call the utility rather than improvising a tool.
- A leak you cannot find the source of — water travels along framing and shows up far from where it started. Shut the main, contain what you can, and let a plumber trace it.
What's a pro job
Replacing a main shutoff that has seized, drips, or no longer fully closes is a plumber's job, and a common one — swapping an old gate valve for a modern quarter-turn ball valve is one of the more worthwhile small upgrades in a house. Anything at or beyond the meter, the water main itself, and adding or moving shutoffs are pro work as well. None of it should wait until the valve is the only thing standing between you and a flooded floor.
The free thing to do today
The most useful move today costs nothing: find your main shutoff, confirm it turns, and make sure the household knows where it is. If it does not work, or you have a leak you cannot stop or trace, describe what is happening and Roger books one vetted, licensed local plumber and confirms the appointment time with you. You see a price range up front, and the plumber confirms the price in person after seeing the job. Homeowners pay Roger nothing, and Roger does not add a markup on the plumber's price.
Describe the problem — Roger matches you to one vetted local pro and books it. $0 to you.
Common questions
- Where is my main water shutoff valve?
- Follow the water supply to where it enters the house — the main valve is almost always within a few feet of that point, on the street-facing side. In a basement or crawlspace it is low on the front wall; on a slab it is often in the garage, near the water heater, or just inside an exterior wall. There is also a valve at the meter outside, but that one usually needs a special key and the street side of it belongs to the water utility, so use the inside main if you have one.
- My main shutoff won't turn or won't stop the water — what do I do?
- Do not force a seized valve until it breaks, especially an old round-wheel gate valve, which can snap off in your hand. If you can, shut off water at a local fixture valve instead, and call your water utility, who can close the water at the street. Then have a plumber replace the main valve — a shutoff that fails when you need it is worth fixing on a calm day, not during a leak.
- How do I stop water from a burst pipe right now?
- Go straight to the main shutoff and close it — a quarter turn on a lever valve, or several turns clockwise on a round-wheel one — then open a low faucet to drain the pressure out of the pipes. If the water is anywhere near outlets, the panel, or an appliance, cut power to that area at the breaker too, and if you cannot do that without standing in water, leave and call for help from outside. Once the water is off, call a plumber to repair the pipe.