My cold water tank sounds as if it is filling all the time and there is a dull roar coming from it continually. It seems to have happened over the last few weeks; no work has been carried out on it or the rest of the plumbing in my flat. There doesn't seem to be any problem with the water flow from taps etc, although I did think the toilet water level was a bit lower than it should be. I can't see any evidence of water leaking from anywhere.
Any suggestions as to what could be causing this and how to fix it?
Cheers!