Eight glasses of water a day is no longer the right formula you should believe in. The right amount is to divide your weight in lbs by 2 to give the amount in ounces you should drink. So for a 160 lb person, this would come to 80 oz or 10 glasses of water. If you are an athlete, the amount is 2/3rd your body weight in ounces. A good indicator is the color of the urine. If it is clear then, you aren’t dehydrated. If it is yellow or gold, you need to drink more. Read this article for more information.