Hello, and welcome to TCS!
First of all, I just wanted to 'remind' you to make sure you change his water throughout the day since all cats like fresh water
Have you been watching his water dish to see if the level of water has went down at all? He's still a kitten so you may have to show him a few times where the water is, and that its ok to drink from that bowl! Most importantly, don't get too worried about it... he'll get used to it and start drinking water like crazy! But if your still concerned after a few days that he isn't drinking- call up your vet- he could be getting dehydrated!