Hi James,
Glad to see you have you new kitten, don't worry about the drinking Maine Coons do drink more than other cats, especialy if the have been having dry food they love water unlike most cats, if you roll up a ball of tin foil or paper you will find him dunking it in his bowl, my first cat used to do this all the time my second kitten maybe not as much.
If he is having regular check ups with the vet with his vacs etc there should be know need to worry, I would only be concerned if he was going really mad with the drinking.
Cherry
Can ou tell me what colour he is James?