Plumbing Questions? Ask a Plumber for Answers ASAP
Is it constantly running, or constantly overflowing?
When you look inside the cistern, you can see the water level is over the top of the overflow pipe into the cistern?
Ok, that means the balltap wants a new washer.
If you are able to rewasher it yourself then it will cure your problem.
Looking at the cistern, it will be the blue cap that unscrews.
You will need to turn off the water to the cistern.
Remove the blue cap and disassemble balltap
Remove old washer
Refit new washer (you wont know which type until you have the old one out)
Refit cap and reassemble balltap
Turn on water and test
Adjust water level.
All done ;-)
The white one next to it that is attached to the float, it unscrews anticlockwise.
Be sure to hold the rest of the balltap to stop it spinning