Supernu, I don't know if there is a specific water graph, but here's what I do to keep an eye on water consumption, specifically: I set up Water as a Custom Nutrition Goal. How? Glad you asked!
On the Food Log page, look for that big pie chart (how cruel to use pie charts on a site that's helping us live more healthfully! hehe). Above and slightly to the left of the chart are 5 tabs: Calories, Nutrition, %-RDA, Cal. Balance and Custom Nutrition Goals
. Custom Nutrition Goals
is the one you want. Click on it and and look a little below for a link called Setup Your Nutrition Goals
. Click that
link and it will take you to a page where you can decide on specific things you'd like to track.
You can tell Fitday what you want to track and what you would like as a minimum/maximum per day. For example, I have it set to give me a maximum Sodium of 1500mg per day and a minimum Water of 1500ml (the Custom Nutrition page uses grams, but since 1ml=1g, it doesn't matter) per day. I don't have a maximum goal for water -- I let my bladder set the max each day
In any event, hope that helps! Good luck with your tracking!