at the breakfast buffet they offer 2 juices, ice water, tea and good American coffee, at the lunch buffet there`s again water, tea and coffee. At dinner they serve a jug of water at your table, with or without ice (most europeans don`t like ice). At the bars they will always serve a free glass of water if you ask. There is only ice water available at the dispensers all the time.
If that sounds modest to you, remember that the prices for drinks were the cheapest i`ve ever had on all my 15+ cruises because there`s no service charge, so it doesn`t really matter. The italian coffee specialities are great, the staff is very friendly and doesn`t push drinks.
Have a great time, the itinerary is wonderful.