How do I turn off the cold water supply upstairs?

To turn off the cold water supply specifically upstairs, you'll need to locate the isolation valve for the upstairs plumbing. If you can't find a dedicated isolation valve, you may need to shut off the entire house's cold water supply. Here's a breakdown:

1. Check for an Upstairs Isolation Valve

• Where to look: Start by checking near any sinks, toilets, or showers/tubs located upstairs. These fixtures often have individual shut-off valves (small, usually chrome or brass), typically located underneath or behind the fixture. They often have a small handle that you turn.
• How to identify: These valves will be connected to the cold water pipe leading specifically to that fixture.
• How to use: Turn the valve clockwise until it's fully closed. Test the cold water tap for that fixture to confirm the water is off.

Important Note: If you only want to isolate one fixture upstairs (e.g., a leaky faucet), finding and using its individual isolation valve is the best approach.

2. If No Upstairs Isolation Valve Exists: Turn Off the Whole House's Cold Water Supply

This is the most common scenario, especially in older homes.

• Locate the Main Stop Cock (Stop Tap): This valve controls the entire cold water supply to your property. It's usually found:

  • Near the kitchen sink.
  • In a utility room or basement.
  • Under the stairs.
  • Near the water meter (often outside the property in a small pit covered with a lid). Look for a small metal or plastic door/cover near the front of your house.

• How to Identify: The stop cock is typically a brass valve with a handle (often a wheel or lever) on it. You'll see a water pipe on each side of the valve.

• How to Turn Off the Water:

  1. Turn the Valve Clockwise: Rotate the handle firmly clockwise until it stops. Don't force it.
  2. Check a Tap: Open a cold water tap (preferably the one furthest from the stop cock, often an upstairs tap) to check that the water flow stops. It might sputter briefly as the water in the pipes drains out.
  3. Turn off Electrical Water Heaters: If you have an electric water heater, switch it off at the breaker panel after you've shut off the water supply. Running an electric water heater without water can damage the heating element. This is important.
  4. Be Prepared for Leaks: Have buckets and towels ready to catch any residual water that might leak from the pipes.

3. Turning the Water Back On

• Slowly Turn the Stop Cock Counter-Clockwise: Open the valve slowly to prevent water hammer (a loud banging noise in the pipes).
• Check for Leaks: Inspect all the pipes and fittings you've disturbed for leaks.
• Bleed the Air: Open all cold water taps one at a time to allow air to escape from the pipes. Let them run until the water flows smoothly.
• Turn the Electric Water Heater Back On: Once the water supply is fully restored, you can turn the electric water heater back on at the breaker panel.