How to isolate your water supply

There are times when you’ll need to turn off your water supply, either to your whole home or to individual taps or showers. This could be because you’re carrying out alterations, upgrades or general maintenance to your plumbing, or because you’ve discovered a leak.

Your stopcock

The main water supply to your home is controlled by a stopcock, sometimes called a stop-tap. It can be found outside your home, by the water meter. There is normally a second stopcock inside your hous

Finding and operating your external stop-cock

Finding and operating your internal stopcock

Stopcock image

You will have been shown where it is during your Home Demonstration Tour. But, if you live in a house, it should be in one of these places:

  • under the kitchen sink
  •  in the downstairs toilet
  • under the sink in the utility room

 If you live in an apartment then it may also be found in:

  • the communal area outside the entrance door
  • in a cupboard along with stopcocks for other apartments

Once you’ve located your stopcock, it’s a good idea to regularly test it to make sure it doesn’t get stuck in one position, and will always be ready to use in an emergency.

It is important to turn off your boiler before you shut off the water to your home, to reduce any chance that your boiler may attempt to run without an adequate water supply.

To turn off your internal stopcock:

  • turn the top clockwise until you can feel resistance, the same as when you turn off a tap.


Isolating individual appliances

Isolating individual appliances

Some of the plumbing in your home will have individual isolation valves, so you can stop the water supply to certain areas without affecting your entire home.

In general there are two types you are likely to come across in your home.

  • The first has a coloured plastic ‘tap’ to switch it on or off, and is used to control the water supply to appliances such as washing machines and dishwashers. They generally look like this:
  • When the plastic handle is in line with the water pipe, the valve is open and water can flow. When the handle is at 90 degrees to the pipe the water is shut off.
  • The second is used to isolate fittings such as taps or toilets. These require a screwdriver to operate, and look like the above image.
  • When the screwdriver slot is in line with the water pipe, the valve is open and water can flow. When the slot is at 90 degrees to the pipe the water is shut off.

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