You can purchase a hot and cold adjustable valve that you can adjust the temperture of the water to a slightly warm mix and that will stop your toilet from sweating. So basically you need to plumb hot and cold to this valve then one line to your toilet. Alsoyou can turn the hot up and the toilet seat will be nice and warm when you sit on it. If you turn it up to much your toilet seat will have a steam mist on it when you sit down (you might not like it) You can get this valve at your local home depot