Short answer: Find the valve where the water line enters your home, usually in a basement, crawl space, garage, utility closet or near the water heater, then turn it clockwise, or turn a lever a quarter turn so it sits across the pipe.
Knowing how to shut off your water can turn a flood into a small mess. Take five minutes now to find the valve before you need it.
Where to find the main valve
- In a basement, often on the wall closest to the street
- In a crawl space near where the pipe comes in
- In a garage or utility closet
- Near the water heater
- Outside near the foundation, especially in warm climates
How to turn it off
- For a round wheel handle, turn it clockwise until it stops. This is a gate valve
- For a lever handle, turn it a quarter turn so the lever sits across the pipe. This is a ball valve
- Open a tap on the lowest floor to drain water from the pipes
- Turn off the water heater if you will be without water for long
If the valve will not turn
Do not force it with a wrench, which can break an old valve. Your water utility can usually shut off water at the curb box near the street, often with a special key. Call them, or a plumber, if you cannot shut off the water.
Turning the water back on
- Close the taps you opened
- Turn the valve on slowly to avoid pressure surges
- Check for leaks where work was done
- Run taps to clear air from the pipes
Mistakes to avoid
- Waiting for a leak before looking for the valve
- Forcing a stuck valve with a large wrench
- Forgetting to turn off a gas water heater when the water is off for long
- Turning the water back on too fast
- Leaving an old, leaky valve in place
When to call a plumber
Call a plumber if the valve will not close fully, if it leaks, or if water keeps flowing after you turn it off. A plumber can replace an old gate valve with a quarter turn ball valve that is easier to use in an emergency.
Frequently asked questions
How often should I test the main valve?
Try turning it once or twice a year so it does not seize.
Can I shut off water to just one fixture?
Yes. Most sinks and toilets have small valves underneath. Turn them clockwise to close.
What if I cannot find the valve?
Check your home inspection report, ask your water utility or have a plumber locate and label it.
Should I replace an old valve?
If it is stiff, leaks or will not close fully, ask a plumber about replacing it with a quarter turn ball valve.
Related
Read our emergency plumber guide and our plumbing guide.
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