A common recommendation is to drink six or eight 8-ounce glasses of water or other fluid every day, according to WebMD. Some adults may need more or less depending on how healthy they are, how much they exercise and how hot and dry the climate is.
The body cannot function properly without adequate amounts of water. According to MayoClinic, one should replenish the body's water supply by consuming beverages and foods that contain water. The Institute of Medicine determined that an adequate intake (AI) of fluid for men is roughly 13 cups, or 3 liters, of total water per day. The AI for women is about 9 cups, or 2.2 liters, of total water per day. According to WebMD, all liquids keep a drinker hydrated, but water is usually the best choice, as it contains neither sugar nor calories.