Which way turns the water off?

Clockwise — righty-tighty — until it stops. Then check by opening the kitchen cold tap; the flow should stop within a minute.

My stopcock is stuck — what do I do?

Don't force it — an old seized stopcock can snap and cause a worse leak. If you can't turn it by hand, use the outside stopcock at the boundary, or call your water supplier. Once the emergency is over, have a plumber fit a modern lever valve.

What if I can't find the stopcock at all?

Use the outside stopcock at your boundary — a small cover in the path or pavement, turned with a stopcock key — or call your water supplier's emergency line. It's worth locating and labelling your stopcock before you ever need it.

Emergency basics

How to turn off your water at the stopcock

Guidance built with working UK plumbers · Last updated July 2026

To stop a leak fast, turn off your internal stopcock — most often found under the kitchen sink — by turning the handle clockwise until it stops. Then open the kitchen cold tap to confirm the flow drops away. Knowing where yours is before an emergency saves the most damage.

Do this first in any leak. Stopping the water at the mains is the single most effective thing you can do to limit damage while you work out the cause.

Turn it off — step by step

Find the stopcock. Under the kitchen sink first. If not there: near the front door, a downstairs cloakroom, an airing cupboard, the garage or utility room.
Turn it off. Clockwise (righty-tighty) until it stops. Don't force a stiff one — see below.
Confirm. Open the cold tap at the kitchen sink; the flow should stop within a minute or so.
Can't find it, or it won't turn? Use the outside stopcock at your boundary (a small round or rectangular cover in the path or pavement) with a stopcock key, or call your water supplier.

Where to look

Location	How likely
Under the kitchen sink	Most common
Near the front door / hallway	Common
Downstairs toilet, airing cupboard, garage, utility	Possible
Outside boundary (path/pavement cover)	Backup — needs a stopcock key

If the stopcock is stuck

Don't force it. An old, seized stopcock can snap and cause a far worse leak. If it won't turn by hand, use the outside stopcock or call your water supplier's emergency line. Once things are calm, have a plumber fit a modern quarter-turn lever valve so it's easy next time. LeakScan gives guidance, not a substitute for a qualified plumber.

Questions, answered straight

Where is my stopcock?

Usually under the kitchen sink. If not, check near the front door, a downstairs cloakroom, an airing cupboard, the garage or utility. There's also an outside one at your boundary.

Which way turns it off?

Clockwise until it stops, then check with the kitchen cold tap.

It's stuck — what do I do?

Don't force it. Use the outside stopcock or call your water supplier, then have a plumber fit a lever valve afterwards.

I can't find it at all.

Use the outside boundary stopcock with a stopcock key, or call your supplier. Locate and label yours before you ever need it.

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