we have 2 water tanks in loft next to each other 1 is cold water and i think the other is for the heating, Now the over flow pipe that sticks out the wall outside is dripping water,do you think that would be coming from the cold tank or heating, do i need to change ballcock (if so which 1 or both) thanks mark.

mark, November 2010

you will have to trace the pipe back to the tank to be sure.if in doubt change both

deano, November 2010