Closing the Main Water Valve Quickly

Before you start

Find the valve now, on a calm day, rather than during an emergency. Look first on the basement wall closest to the road: the service pipe comes in there, and the valve and meter sit just inside. In finished basements it may hide behind an access panel, under the stairs or inside a utility room.

• Look for the water meter first; the valve is usually just before it
• In condos, the suite valve is often in a utility closet or behind a panel near the water heater
• Townhouses sometimes have a shut-off shared with neighbours, so check your corporation's notes
• Keep a flashlight near the valve

Step by step

1. Recognise the valve. A circular wheel means a gate or globe pattern; a flat lever means a ball valve.
2. Close a ball valve. Turn the lever a quarter turn until it sits perpendicular to the pipe.
3. Close a wheel valve. Turn clockwise until it stops firmly. It may take several full turns.
4. Relieve pressure. Open a faucet on the lowest floor to drain the remaining water from the lines.
5. Protect the water heater. For a lengthy shutdown, turn a gas tank down to pilot, or cut the breaker to an electric one's breaker.
6. Confirm. Check that no fixture runs and that the meter dial has stopped.

Mistakes to avoid

• Using a wrench on an old wheel handle. Brittle stems snap, and you may end up with a leak at the valve itself.
• Confusing it with a fixture valve. A shut-off beneath a sink controls only that sink.
• Turning the curb stop. The valve at the property line belongs to the municipality and requires a special key.
• Forgetting the heater. An electric tank with its elements on and no water can be damaged.

Label it now

Once you have found the valve, tie a bright tag to it and write which way closes it. Show everyone in the household where it is. Fixture shut-offs under sinks and behind toilets deserve the same treatment, since closing a single fixture keeps the rest of the house in service during a minor repair.

When to call

Book a visit if the valve refuses to turn, will not close completely, or leaks once turned. Old multi-turn valves are common in homes built before the 1990s and are worth replacing with a ball valve; see main shut-off valve replacement. If water is already flowing where it should not, our urgent call-out notes set out the next steps, and our guide to a home plumbing emergency kit lists what to keep nearby. Burst lines are covered under burst pipe repair.

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