Drinking more than you think you want, especially during hot weather, helps prevent dehydration. While water is great choice, there are other beverages like milk, juices, and soft drinks, that will pump water back into your body and keep you hydrated. You can also get water from some foods, especially fruits and vegetables. In an average diet, it's estimated that solid foods provide between three and four cups of water a day. Many people enjoy drinking flavored beverages instead of plain water.
Alcoholic drinks have a dehydrating effect, as well.
Every system in your body depends on water, and our bodies are effective at extracting water from foods and beverages. Water regulates your body temperature, removes wastes, carries nutrients and oxygen to your cells, cushions your joints, and helps dissolve vitamins and minerals. There's even some evidence that water helps prevent certain diseases. People who have had kidney stones can prevent further stones by drinking lots of fluid. In one study, women who drank more than five glasses of water a day had a 45 percent less risk of colon cancer than others in the study who drank two or fewer glasses a day.