A Must Have
I have been using WaterMinder for a couple of months. It keeps track of hydration, allows for customization in settings and gentle reminders to keep you on pace to meet you daily goal. Badges/Rewards are presented for accomplishments. You can see you data/stats within the app for quick review or integrate stats in the Apple Health app.
Stew the Doodle Fan about
Water Tracker: WaterMinder, v3.1