The first thing you should check for is water leaking past the flapper. Food color in the tank will let you know if you have a running leak. If water is allowed to "run" then the water will be very cold. Terry
: The sweating is a result of temperature differential from the well water and the room temperature meeting at the ceramic surface and condensating. There are insulating materials you can use on the tank and toilet bowl, or you can make your own slipcovers for the tank and lid from terrycloth. More
: : How con I prevent my toilet from sweating. It is not just the tank but the bowl too. We get our water from a well.