I just moved in to a 5 year old house. The toilet on the first floor has hot water in the tank. When I have guest and the toilet is flushed 4 or 5 times, the water gets very hot and creates lots of steam. I called the builder and said I believe the hot supply is connected to the tank instead of the cold supply. He said that was impossible and refused to come and look at the toilet. Is there any other explanation? Also, the basement is finished so I cannot see the supply pipes leading to the first floor basement. I need a second opinion before I have someone open up my finished basement ceiling.