There's no denying that water is one of the most important beverages you should stock up on. If it weren't healthy, your doctor wouldn't advise you to drink 8 glasses of it every day. Water is an important driver of health. Without enough water, your body will not be able to function properly. Water is a good source of oxygen, and as you already know, oxygen is needed by your heart and lungs in order for you to breathe and in order for your blood to supply nutrients all over your body.