Turn off your water mains
Could save £1,000s in flood damage
5 mins · Beginner · Essential emergency skill
Last updated: March 2025
Before you start
Every adult in the household should know where the main stop cock is and how to turn it off. If a pipe bursts, you may have less than a minute to act.
The stop cock is almost always under the kitchen sink in UK homes. Take 5 minutes now to find it, before you ever need it.
Tools needed
- ✓No tools usually needed — most stop cocks can be turned by hand
- !Flat-head screwdriver — buy: some older stop cocks require a screwdriver in the slot — buy: already in most homes
- !Stop cock key — buy: buy: £3–5 from a plumber's merchant — useful if the stop cock is stiff or in a pit outside
Find the internal stop cock
Check under the kitchen sink first — this is where it is in 90% of UK homes. It is a brass valve on the pipe coming through the wall or floor. It may have a lever handle or a round knurled handle.
Where beginners go wrong
Not finding the stop cock until there is already water everywhere — find it now, not in an emergency.
Turning clockwise to open and anticlockwise to close — it is the opposite. Clockwise closes the valve (right-tight, left-loose).
Assuming a lever handle is closed when it is parallel to the pipe — parallel means open, perpendicular means closed.
Stop and call a plumber if...
The internal stop cock will not turn off even with maximum force
Water is still flowing after the stop cock is turned off — call your water supplier immediately
The stop cock is leaking itself
Cost breakdown
What you just learned
You now know how to shut off water to your whole home in seconds. This is the single most important plumbing skill — it limits the damage from any burst pipe or appliance failure.
What this unlocks
With confidence in turning off the mains, you can safely tackle any plumbing job: fixing leaks, replacing taps, installing washing machines, and more.
✅ Completed by 5,612 people
⚠️ Watch out if you rent
Ask your landlord or letting agent where the stop cock is when you move in — this is a basic piece of information they should provide. Also ask about the external stop cock location.