If your pipes burst due to freezing, sewage backup, or some other kind of rupture, large volumes of water may flow through your home, resulting in towering bills and the loss of irreplaceable valuables. The causes behind most leaks aren’t always in your control, but one step you can take is to ensure everyone in your household is familiar with the location and operation of your home’s main water shut-off valve. By doing so, you’ll be prepared to halt the supply of water to your home, stopping the leak before you’ve identified and repaired the immediate cause, and averting costly damage.
It’s also a good idea to leave the valve closed if you’ll be away from your home for an extended period of time, so leaks don’t occur and worsen with no one there to stop them.
Prepping to Shut Off the Main Water Valve
You’ll need to know what to look for when shutting off your main water valve. Your main water shut-off valve will be one of two types.
If you see a straight handle sitting parallel to the pipe, it’s a ball valve. It has a lever-style handle, making it easy to turn without additional tools.
If you see a round handle resembling the faucet on a spigot, it’s a gate valve. Over time, gate valves can become tight and difficult to operate by hand if they’re not used. You may want to regularly check in to confirm the handle works so you don’t discover it’s stuck in the middle of a major leak.
No matter what type of valve attaches to your pipes, it may be difficult to operate by hand. Try adding some spray oil or lubricant, but if that doesn’t do the trick, call in a pro sooner rather than later since it may be corroded and at risk of breaking.
Check the property inspection report: If you have the property inspection report from when you bought the house, you can determine the location of the main shut-off valve. In the plumbing section of the report, you should find a written description and a photograph of the main shut-off valve.
Look inside the house: If you receive water from a municipal supply rather than a well, the shut-off valve will be located near the house perimeter on the side closest to the street. You should check utility areas, such as the basement, garage, and laundry room, along exterior walls closest to the street. Since the valve is usually installed 3 to 5 feet from where the pipe enters the house, the valve will be even with the grade.
Check outside the house: In warmer climates, the shut-off valve is sometimes located on the water company’s pipe, close to an exterior wall of the house where it enters your home. If you don’t have an indoor shut-off valve, you should go straight to the meter box. Look on the sidewalk or close to the property line for a metal lid on a cement box, often labeled “water.” Opening it may require a meter key, which you can purchase at a local home improvement store.
Turn Off the Water Supply
Photo: Michael / Adobe Stock
Now it’s time to switch your water supply off. If it’s a ball valve, turn the valve clockwise until it’s fully perpendicular to the pipe. If it’s a gate valve, turn the handle all the way clockwise until it’s tight. Use spray oil or other lubricant to loosen the valve if you have difficulty turning it. Whichever position you leave it in, make sure it’s fully open or closed since allowing water to drip through a partially open valve can corrode the metal.
To access the shut-off valve within the curbside water meter box, insert the meter key into the hole and turn it counterclockwise. If it has a ball valve, turn that counterclockwise until it loosens. Once unlocked, use the key as a lever, tilting it toward the outer edge to lift up the lid. Look for the ball valve closest to your property line. As in your home, if the handle is turned parallel to the pipe, it’s open. Use the meter key to turn it clockwise until the handle is fully perpendicular to the pipe closest to it. Don’t touch the city’s shut-off valve—there are criminal penalties for tampering with a city water meter.
Run the Hot and Cold Taps
Once you have closed the shut-off valve, open up the hot and cold water lines in a sink on the lowest floor and run the taps until they empty fully. This step confirms that the supply has indeed been cut off, plus it releases pressure from the system.
Turn the Water Supply Back On
Once you’re ready to turn your water supply back on, simply twist the valve counter-clockwise to get the water flowing again. Check that everything is in working order by testing the hot and cold water taps in your sink.
DIY Shutting Off Main Water Valve Vs. Hiring a Pro
If you’re shutting off your water supply due to an emergency leak or plumbing issue, you may not have time to wait for a professional plumber to arrive. In that case, you’ll need to locate and shut off the main water valve on your own.
However, if it’s not an emergency situation, you can hire a professional plumber near you to help you shut off the water supply and diagnose the problem. If your shut-off valve is inside a water meter box and you’re unsure which valve is which, call a local plumber or your utility company to send someone out to help you.
Check out answers to common questions about locating and using your water shut-off valve.
Why is it important to know how to turn off the water supply?
Your home’s plumbing system features a series of different shut-off valves allowing you to stop water flow to the whole property, the interior of the house, or to particular appliances. The precise number and location of these valves vary from home to home, depending on factors like when the house was built, the impositions of local geography and building codes, and the building type.
Suppose you've ever performed even minor DIY repairs to your sink or toilet. In that case, you're likely familiar with the isolation valves located on pipes in immediate proximity to an appliance, typically beneath it. These valves come in handy if the problem is localized to a specific appliance since they control the water flow, but they will not help you if the leak affects other parts of your plumbing.
When the running water isn’t isolated to a particular area, you’re going to need to identify the main shut-off valve to stop the flow and buy yourself time to fix the underlying problem.
What if I can't find my main water shut-off valve?
It can be tricky to locate your water shut-off valve for the first time, especially if you’re in a rush. Look out for the bright green or red knob that stands out among the rest of the plumbing system. If you’ve searched the interior and exterior of your house and consulted your property inspection report with no luck, contact your local utility company for help.