The most likely reason is a worn washer; that can be easily replaced as long
as there is an isolating valve (there should be) fitted to the incoming
Even if you have to fit a new valve that is not difficult and with the
proper tools could be done in under 30 minutes.
Check first that the ball is not leaking or waterlogged; gently lift it up
and note if the water stops coming in. A new ball is very easy to fit.
I have a cold water tank in the loft, and my overflow pipe drips
outside, I think it is because the ball valve may be long overdue to be
changed. Is this a reason for the overflow to be dripping.
How do I go about such a job? is it really as easy as changing it like
for like ? I dont want to pay £75 for a quick job that I can do
myself. How long is such a job likely to take me ?
Any help would me much appreciated.