Water helps keep your body hydrated, which is important for keeping all of your bodily systems working properly. It keeps tissues moist and cells healthy, and it helps remove toxins and waste. It helps the body regulate temperature and helps prevent dehydration (even mild dehydration can negatively affect your energy levels).
How much water is enough? It's going to depend on your lifestyle, your habits and how your individual body works, but the Institute of Medicine suggests roughly 2 to 3 liters of total fluids every day (that's 2.2 liters or 9 cups for women and 3 liters or 13 cups for men every day) [source: Mayo Clinic].
Bored with water? Many fruits and vegetables add to your water intake while boosting your vitamin and mineral intake at the same time. Watermelon, radishes and zucchini, for example, all contain high amounts of water per serving -- more than 90 percent water by weight.