[@Halvtand] Ok, we'll say that he learned the technique on the scroll practicing with Hiroshi, only the 2 of them. And about the temp. control, I'll say that it doesn't effect any kind of water except the one produced by his jutsus. Seem fair? Now I can't throw someone in the lake and freeze/boil the sh*t out of them XD(or just freeze/boil their blood...) And the temp. can be controlled by the user at the start of the jutsu and every time he gets into contact with his water/steam/ice he can change it.***If it is a small amount of water(glass size) he can change it's temp from longer ranges(some feet away)*** And needless to say the more water he changes the temp. of the more chakra he uses. he So where does this technique classify? (E/D/C/B etc.) 
Edit: I could remove the ice/steam part if it seems too op and make it hellishly hot and ...hellishly cold?(you know, many people view hell with different properties)