The water filling my system is so cold that a lot of condensation forms on the outside of the toilet's tank. There is enough for the water to fall onto the floor, which is slowing causing damage.
Is there a way of stopping this? What could I do to make sure the water being used by the toilet is not so cold?
Empty the cistern (tank) dry it out and use waterproof glue to fix polystyrene sheet, about 1 cm thick, to the inside of the tank. This will insulate the cold water from the walls of the cistern and so stop condensation.