Expert advice from Bob Vila, the most trusted name in home improvement, turning fridge on and off remodeling, home repair, and DIY. Learn what to do before you’re faced with a plumbing emergency.

We may earn revenue from the products available on this page and participate in affiliate programs. Chances are, there will come a time when you’ll have to turn off the water supply to your home: You may need to do so for a scheduled plumbing repair, or before leaving on a long trip. Then there are the emergency situations, such as when a pipe bursts somewhere behind the drywall or your bathroom is flooded with water, when you’ll need to cut the water off—and fast. There’s no one universal spot in every house where water supply valves are located, so it could take some time to find them—time that you won’t have if water is rapidly soaking through the second-floor ceiling.

Show family members, too, where the valves are and how to cut them off quickly. There are a wide variety of valves that are used in commercial, industrial, and institutional plumbing scenarios. However, there are two types of valves that are commonly used in residential homes as building control valves: gate valves and ball valves. Gate valves consist of a circular handle attached with a stem to the body of the valve. When you turn the handle, it slowly closes a gate inside the body of the valve, blocking the flow of water. Turning the valve in the opposite direction will open the gate and allow the water to flow freely.

Ball valves are the preferred type of valve for home use because they are less likely to seize up or develop leaks over time. You can recognize ball valves by their lever-style handle. As the name indicates, there is a ball inside the body of the valve which has a hole through the center. The main water shutoff valve is usually located on the main water line, where it enters the home. In most cases, this will be in a basement, cellar, or crawlspace because the water line extends from the neighborhood water main and enters the home from under the ground. Water supply pipes from the city typically run from the street side of your house to the indoors.

So check out utility areas—such as the garage, laundry room, or basement—along exterior walls facing the street. A likely place to start looking is near your water heater. In some warmer climates, the shutoff valve may be located outside the home on an exterior wall. Start looking for it near your outdoor faucet. If you can’t find the valve in or around the house, it’s time to hit the street.