I am in week 9 of CD and have never had more than the minimum amount of fluid alongside my CD sachets.
So far i have lost 36lbs, which i am completely satisfied with. Yes, some people have lost more, but i do not believe in dragging myself down by forcing more drink down.
If you can manage more comfortably, then try and see whether your losses increase with a greater fluid intake.
I only drink fizzy water, black coffee & tea and green/mint tea. Never plain still water.