If you close a stop tap fully and the water is still passing through the tap then it is probably due to a faulty or worn tap washer. This can be replaced for a few pence, but it is essential that the water is isolated before you attempt to do this, so ensure that the water is isolated at the main isolator on the border of the property before attempting this.
Grip the body of the stop tap with a pair of adjustable water pump pliers, then with a suitable spanner turn the large nut in the centre of the stop tap anti-clockwise.
Then unscrew the handle and assembly from the body of the tap.
The rubber washer on the end of the assembly can easily be pulled off.
Remove the rubber washer.
Replace the rubber washer with a new one, this simply pushes onto the end of the assembly.
Wrap some PTFE tape around the thread of the assembly.
Screw the assembly into the body of the stop tap and then re-tighten using the water pump pliers and suitable spanner.
