: : Are there any draw backs to running a hot water supply line to my toilets, to prevent sweating? My father in law said he heard it would crack the tank.
: Your father-in-law is correct, the tank & bowl will crack with straight hot water feeding it possibly causing severe injuries. There are valves available that mix hot & cold but most toilets that I've seen that sweat a lot are usually in need of repair.
Had the same problem every summer in our family's home served by our basement's in-ground constant 55 deg spring water. Dad solved it by coiling 50 ft of garden hose in the bathroom closet and a bit of creative plumbing connecting it to the toilet. According to my brother it's still working after over 15 years with only minor maintenence and a few small repairs. Cheers, Rughead.