So how much fluid does the average, healthy adult living in a temperate climate need? The Institute of Medicine determined that an adequate intake for men is roughly about 13 cups (3 liters) of total beverages a day, and the adequate intake for women is about 9 cups (2.2 liters) of total beverages a day.
To be more specific, take 1/2your body weight in ounces, and multiple it by .0296. (1 Ounce = .0296 Liter)
Example: Body Weight = 220lbs; divided by 220/2=110 lbs; multiple 110 lbs x .0296 Liters = 3.25 Liters