Finding Your Main Shut-Off Valve

Why it matters

Water from a split supply line can pour out at many litres a minute. Every minute spent searching for the valve is more water in the ceiling, walls and floors. Insurers and plumbers agree: the cheapest flood protection is knowing how to stop the water.

Step by step

1. Trace the supply inward. In most Burlington houses the water service comes through the basement floor or front foundation wall, toward the street. Look near the water meter, which Halton Region installs and reads.
2. Identify the valve. Expect a valve just past the meter. A round handle signals an older gate or globe valve; a flat lever signals a ball valve.
3. Check behind finishes. Finished lower levels tend to tuck them behind a hatch, inside a closet or beneath the stairs.
4. Test it gently. Close the valve and open a tap upstairs. Flow should stop within a minute. Then reopen the valve fully.
5. Label it. Tie a bright tag to it and show the whole household.

Common mistakes

• Wrenching on a decades-frozen round handle, which can break it or start a stem leak.
• Confusing the main valve with the water heater supply valve.
• Blocking the valve with shelves, drywall or stored boxes.
• Assuming a slab-on-grade or newer home has no valve; it is somewhere, often near the water heater.

When to call a plumber

Phone us if it is stuck, drips once turned, lets water past, or stays hidden. Swapping a tired gate valve for a lever-handle ball valve is quick work that earns its keep in the first emergency. Our shut-off valve replacement page explains how it is done. For the outside curb stop, owned and operated by Halton Region, call the Region rather than trying it yourself.