How much water needs human body a day?

Varies: A simple rule is enough that you pee every 6-8 hrs. You get fluid value from both liquids and many foods you eat. Apple sauce is 95% water, most vegetables 60%. I consider specifying a target amount worthless.Anyone with normal kidney function can relax & ignore those who specify glasses per day or other ideas.

Agree with Dr. F: To make sure that you are adequately hydrated, drink enough water daily so that your urine is mostly colorless. Have a healthy diet, exercise 30 minutes/day, drink plenty of water, have safe sex, no tobacco alcohol weed or street drugs. For nutrition: http://www.choosemyplate.gov/. Wish you good health!