Your body gives you clues. If your pee looks like lemonade, you’re golden (pun intended). If it looks like apple juice, you need to drink up. Also, if your mouth feels like the desert in a Western movie, listen to it.
B Fit B Hydrated - The Braden Aboud Memorial Foundation
Are you sweating? Did you just mow the lawn in July heat? Did you crush a workout at the gym? Double your water for that hour. Your muscles are basically crying "thank you" when you hydrate after exercise.