Every house should have a main water shut off valve. This is the valve that stops water from flowing into the home. If a pipe starts leaking, a toilet overflows, or a supply line bursts, knowing where this valve is can save time and limit damage.
Many people do not think about it until they need it. That is why this matters. A quick shutoff can make a plumbing problem easier to control.
Bottom line: Find your main shut off before an emergency so you can act fast when water needs to stop.
The main water shut off valve controls the flow of water into the house. When it is fully closed, sinks, toilets, showers, appliances, and other fixtures should stop getting water.
This is not the same as a small shutoff under a sink or behind a toilet. Those valves control one fixture. The main shut off affects the whole house.
In many homes, the valve is close to where the main water line enters the house. That entry point is often on the side of the home facing the street. Start there first.
If your house has a basement, look along the front wall or near the spot where the water line comes through the foundation. In some homes, the valve is just a few feet inside that entry point.
In a crawl space, the valve may be near the access opening or along the main water line under the floor.
In slab homes, the valve is often inside a utility room, laundry area, or garage. It may be mounted low on the wall, close to the water heater, or near where the water line enters the home.
Sometimes the main shut off is near the water heater because that area is close to the incoming plumbing. In other homes, it is near the front foundation wall, especially if the street and water meter are in front of the house.
Some houses have an exterior shutoff near the meter, in a utility box, or along an outside wall. Even so, many homes still have an indoor main shut off too. The indoor valve is often easier to reach in a hurry.
If you are in an apartment or shared building, access may be different. This page focuses on whole-house shutoffs in houses.
Main water shut off valves are usually one of two common types.
A gate valve usually has a round handle. You turn it clockwise to close it. These are common in older homes. Sometimes they take several turns to fully shut off the water.
A ball valve usually has a straight lever handle. Turn the handle a quarter turn so it sits across the pipe. That normally means the water is off.
If the handle is parallel with the pipe, it is usually open. If it is across the pipe, it is usually closed.
First, stay calm and move carefully. If water is spraying near outlets, cords, or appliances, avoid standing water and use extra caution.
Next, find the main water shut off valve. Once you have it:
Do not force the valve if it feels stuck. Older valves can break. If it will not move, or if it starts leaking around the handle, stop and get help.
Once the water is off, focus on limiting damage and deciding on the next step.
If water ran for a while before you reached the valve, our Water Waste Calculator can help you estimate how much may have been wasted.
If a leak or open line kept running before you could shut the water off, the calculator can help you estimate the likely water loss.
Sometimes the main water shut off valve is hidden behind storage, painted over, corroded, or simply hard to identify. In other cases, the valve closes only part way and water keeps running.
If that happens, do not assume the problem is under control. A valve that will not close fully can leave water flowing or pressure in the system.
Need help with a plumbing issue right now? You can get answers from verified plumbing technicians online before you decide on the next step.
If the problem is urgent, read our guide on when and how to find an emergency plumber near you.
You should get professional help quickly if:
This page is about finding and using the main shutoff. It is not a full repair guide. If the valve itself is bad, or the problem continues after shutoff, a plumber is usually the right next step.
Your main water shut off valve is one of the most useful things to know about your house. Find it before you need it. That way, if a leak starts, you can act faster and limit the damage.