Whether you’re fixing a drip, replacing a cartridge, or fitting a brand-new mixer tap, turning off your water supply is the essential first step. Working on live pipework can quickly turn a quick DIY job into an expensive indoor flood!

Here is how to safely isolate the water to your kitchen tap in under 5 minutes.

Method 1: Using Under-Sink Isolation Valves (Easiest)

Most modern UK kitchens have individual isolation valves fitted on the pipes directly below the sink. These allow you to turn off water to the tap without cutting off supply to the rest of the house.

1. Open the Cupboard

Clear out the space beneath your kitchen sink. Look at the copper or flexible plastic pipes running up toward the base of the tap. You should see two pipes: one for hot water and one for cold.

2. Locate the Valves

Look for a small metal joint on each pipe featuring a small round face with a flat slot in the middle (like a flathead screw).

3. Turn the Slot

  • Take a flathead screwdriver and insert it into the slot.
  • Turn the slot a quarter turn (90 degrees).
  • How to tell it’s off: When the slot runs parallel with the pipe, the water is ON. When the slot is perpendicular (at a right angle) to the pipe, the water is OFF.

Method 2: Using the Main Stopcock (If No Valves)

If your pipework doesn’t have local isolation valves, you will need to turn off the main water supply to your home.

1. Find Your Stopcock

In most British homes, the internal main stopcock is located:

  • Under the kitchen sink
  • In an under-stairs cupboard
  • Near the front entrance or in a utility room

2. Turn It Off

Grip the valve handle (usually a brass wheel or lever) and turn it clockwise until it stops turning tightly.

Final Step: Drain the Lines!

Once you have turned off either the isolation valves or the main stopcock:

  1. Open both the hot and cold sides of your kitchen tap fully.
  2. Allow any trapped water inside the spout and upper pipework to run out into the sink until the flow stops completely.

Once the tap stops dripping and runs dry, your water supply is safely isolated, and you are ready to start your repair!

When to Call a Professional Plumber

Isolating your water should be straightforward, but stopcocks and valves can fail over time. You should call an expert if:

  • The under-sink isolation valves are seized or won’t turn.
  • The main stopcock is leaking, stuck solid, or spinning without closing.
  • Water keeps running out of the tap even after fully closing the valves.

Need Help with an Urgent Plumbing Repair?

If you’re stuck with a seized stopcock or a sudden pipe leak, Mr24HourPlumber is here 24/7. We provide fast, reliable emergency plumbing support across the region to keep your home safe and dry.

Contact Mr24HourPlumber today for expert plumbing assistance!