I have written to the developer twice, and he has not responded. This app does not work right. I have never seen the charts working right. As of today, the current version is putting up big screen describing an error every time I enter a glass of water, which I have to dismiss. If you want a good app for hydration, just download AddWater. This was not money well spent.
ijudy about Water Habit - Drinking Water Reminder and Tracker