Where Is My Stopcock? How to Find It

Knowing where your stopcock is takes two minutes to find out and can save thousands of pounds of damage. Almost nobody looks until water is already coming through a ceiling — and that is precisely the moment when hunting through cupboards is least useful.

Find it now, and while you are there, check it actually turns.

You Have Two Stopcocks

The internal stopcock is inside the house, and it shuts off water to the property. This is the one you want in an emergency.

The external stopcock sits at the boundary, usually under a small metal or plastic cover in the path or verge. It belongs to the water company and needs a long-handled key to reach. Use it if the internal one has failed.

Where to Look Inside

In rough order of likelihood:

1. Under the kitchen sink. By far the most common. Look at the back, behind the cleaning bottles, on the pipe that feeds the cold tap.
2. Downstairs cloakroom or utility room, on the pipe entering the building.
3. Under the stairs, in the cupboard.
4. Near the front door in older properties — sometimes under floorboards with a small hatch.
5. Garage or outbuilding, particularly where that is where the main enters.
6. Under a bath panel, in some flats and newer builds.
7. In a service cupboard in a block of flats, sometimes shared.

Your water company can confirm where the external stopcock sits if you cannot find it — for this area that is Anglian Water. Inside, you are looking for a brass or chrome valve on the incoming pipe — either a small wheel-shaped handle, or a lever. It is usually on the pipe that feeds the kitchen cold tap, because that tap is fed straight off the main.

How to Turn It Off

Clockwise closes it. Righty-tighty, the same as a tap.

A wheel handle may take several full turns. A lever type closes with a quarter turn, and is off when the lever sits across the pipe rather than along it.

To confirm it has worked, open the kitchen cold tap. It should run briefly as the pipe empties, then stop.

If It Will Not Turn

Stopcocks seize because they sit untouched for years and limescale builds around the spindle. This is very common in hard water areas.

• Do not force it. An over-torqued old brass valve can snap, and then you have a full-bore leak instead of a controlled one.
• Try firm, steady pressure rather than sudden effort. Penetrating oil on the spindle and ten minutes of patience helps.
• If it still will not move, go to the external stopcock at the boundary.
• If neither works, call your water company — they can isolate at the boundary.

Prevent it seizing

Water UK recommends householders know where their stopcock is and check it works before they need it. Turn it fully off and back on twice a year. That single habit keeps it free and tells you it works before you actually need it. It takes thirty seconds.

Leave it a fraction back from fully open — a quarter turn — so it cannot bind in the open position.

Finding the External Stopcock

Look for a small round or rectangular cover in the path, driveway or grass verge near the boundary, often marked with a W. Lift it and you will see a vertical shaft with the valve at the bottom, sometimes a metre down.

You need a stopcock key — a long T-shaped tool, inexpensive from any DIY shop and worth owning before you need it. Reaching in with a hand or improvising with a broom handle rarely works.

The chamber is often full of soil or water. A torch and something to scoop with helps.

What to Do in an Actual Emergency

1. Turn off the stopcock — clockwise.
2. Open all the cold taps downstairs to drain the system quickly and reduce what is left to leak out.
3. If water is near electrics, turn off the consumer unit before going anywhere near it.
4. Contain what you can — buckets, towels, and a hole poked in a bulging ceiling over a bucket is better than the whole thing coming down at once.
5. Then call someone. With the water off, you have time.

Our guide to turning off the water at the mains goes through this in more detail.

Frequently Asked Questions

My stopcock is under the kitchen sink but I cannot reach it.

Clear the cupboard now rather than during an emergency, and keep that area accessible. If it is genuinely unreachable, it is worth having a lever valve fitted somewhere sensible.

Does turning off the stopcock stop the heating too?

It stops the supply refilling the system, but a sealed heating system holds its own water and radiators will still contain water. For a heating leak you may also need to isolate the boiler.

Is the external stopcock mine or the water company's?

It belongs to the water company, but householders are generally permitted to operate it in an emergency. Turn it gently — they are often old.

I live in a flat and cannot find one.

Check under the sink, then in any service cupboard on the landing. Managing agents usually know. Some blocks have a shared riser valve serving several flats, which the building manager operates.

Worth Doing Before You Need It

Find yours today, label it, make sure it turns, and tell everyone in the house where it is. If it is seized or in an impossible position, we cover Milton Keynes and the surrounding area for emergency plumbing and valve replacement. Get in touch — replacing a seized stopcock is a small job compared with the flood it prevents.