It is very important to drink enough water. If you do not drink enough water throughout the day, you can become dehydrated and that can cause very unpleasant symptoms like headaches, stomach problems and fatigue. The human body is made up of roughly 60% water. The amount of water that everyone should drink depends on the individual and their needs as well as how much the exercise or sweat. Everyone is losing water during the day that needs to be replenished, primarily from sweat and urine.
Doctors often suggest 8 8 ounce cups of water a day which equates to roughly a half of a gallon. There are other people who feel like this is not enough water and suggest drinking up to a gallon of water a day. This is especially good for those who are very active or trying to lose weight.