Every day you lose water through your breath, perspiration, urine and bowel movements. For your body to function properly, you must replenish its water supply by consuming beverages and foods that contain water. So how much fluid does the average, healthy adult living in a temperate climate need? About 15.5 cups (3.7 liters) of fluids for men About 11.5 cups (2.7 liters) of fluids a day for women These recommendations cover fluids from water, other beverages and food. About 20 percent of daily fluid intake usually comes from food and the rest from drinks.
You’ve probably heard the advice, “Drink eight 8-ounce glasses of water a day.” That’s easy to remember, and it’s a reasonable goal. Most healthy people can stay hydrated by drinking water and other fluids whenever they feel thirsty. For some people, fewer than eight glasses a day might be enough. But other people might need more.