Water is your body's principal chemical component and makes up about 60 percent of your body weight. Every system in your body depends on water.
So how much water do you need?
The Institute of Medicine determined that an adequate intake for men is roughly 3 liters (about 13 cups) of total beverages a day. For women is 2.2 liters (about 9 cups) of total beverages a day.
What about the advice to drink eight glasses a day?
Everyone has heard the advice, "Drink eight 8-ounce glasses of water a day." That's about 1.9 liters, which isn't that different from the Institute of Medicine recommendations. "8x8" is easier to remember just keep in consideration that all liquids, not only water, count as intake.