The U.S. Department of Agriculture recommends different amounts of water based on age, sex and health status. The specific recommendations are based on the amount of water lost on a daily basis through perspiration, respiration, urination or metabolism. The USDA began setting dietary recommendations for water to help individuals avoid dehydration. The USDA recommendation is higher for those who live in hot, humid climates and for those who engage in prolonged exercise.
People need from under one liter a day to nearly four liters a day depending on their age, sex and health status. One liter equals 4.23 cups. Newborns and infants need 0.7 to 0.8 liters of water a day from breast milk or formula. Toddlers need 1.3 liters and young children up to eight years need 1.7 liters daily. Boys, ages nine to 13 need 2.4 liters daily. Teenage boys and adult men need 2.7 liters. Girls, ages nine to 13 need 2.1 liters and teenage girls need 2.3 liters. Adult women need at least 2.7 liters of water each day. Women need at least 3 liters of water during pregnancy and 3.8 liters daily for lactation.
Basis for Recommendations
Up to 80 percent of your body weight is water. Muscle tissue is comprised of mostly water and protein. Your body also needs water to help digestion, to stay cool, repair or regenerate cells, keep blood pumping through your veins and to help flush toxins out of your body. Your body uses different amounts of water for these activities everyday, and much more in hot, humid weather or during exercise.
Meeting the Recommendation
People consume 80 percent of their daily water in beverages, and 20 percent of their daily water in foods, according to the USDA. The USDA does not place the value of any one single source of liquid water above another. You can get clean and safe mineral-rich water straight from your tap, or purchase bottled water.
Water is also present in just about every food that we eat. Water-bearing fruits such as apples, oranges, and melons are good dietary sources of water and can help you get you fulfill your daily water needs. Each serving of fruit contains one-half cup of water.
The USDA sets the Dietary Reference Intakes and updates them every few years. These guidelines set the standard for a healthy diet for healthy children and adults, and provide a frame of reference for state and federal nutrition assistance programs. The recommendations are based on a comprehensive meta-analysis by the National Academy of Science researchers of available peer-reviewed literature on water needs.