They drink very rarly.
Well I wouldnt say that.

They drink more often than you think, it's just that more times than not you dont see them drink. But again...each BP is different.

Cheetah I have only seen a handful of times, but he's not in a room that I frequent much. Monty Joe on the other hand, I say I see him hit the water dish a minimum of five times a week but im in this room alot and who knows if he is drinking when Im asleep, but im sure he does.
I'm afraid he be getting a bit dehyrated
First time herp...you and your bp are pretty new to each other, and you just havent caught him drinking yet. He's more than likely drinking. As long as he has a well rounded body no wrinkly, bunchy skin he be aiight...lol