Do you bring up his water at a certain time, or does he have free reign to water? From DAY ONE, I bring up my 11 wks old water at 7, and he goes to bed at 9:30. I make sure he has some water RIGHT BEFORE I bring it up, and only ONE NIGHT was he really wanting water, but that was because I let him go about an hour of chewing on a tendon, and he was THIRSTY!!! Learned my lesson
Thats my only suggestion, because I am new