Without water, your body would stop working properly. Water makes up more than half of your body weight, and a person can't survive for more than a few days without it. Why? Your body has lots of important jobs and it needs water to do many of them. For instance, your blood, which contains a lot of water, carries oxygen to all the cells of your body. Without oxygen, those tiny cells would die and your body would stop working.
Water is also in lymph (say: limf), a fluid that is part of your immune system, which helps you fight off illness. Water helps keep your temperature normal. You need water to digest your food and get rid of waste. Water is needed for digestive juices, urine (pee), and poop. And you can bet that water is the main ingredient in perspiration, also called sweat.
Besides being an important part of the fluids in your body, water is needed by each cell to work.
Your body doesn't get water only from drinking water. Any fluid you drink will contain water, but water and milk are the best choices. Lots of foods contain water too. Fruit contains quite a bit of water, which you could probably tell if you've ever bitten into a peach or plum and felt the juices dripping down your chin. Vegetables also contain a lot of water — think of slicing into a fat tomato or crunching into a crisp stalk of celery.
How Much Is Enough?
Because water is so important, you might wonder if you're drinking enough. There is no magic amount of water that kids need to drink every day. The amount kids need depends on their age, body size, health, and activity level, plus the weather (temperature and humidity levels).