What do you, the trees, and a hamster have in common? Give up? You all need water. All living things must have water to survive, whether they get it from a water fountain, a rain cloud, or a little bottle attached to the side of a hamster cage. 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). Usually, kids drink something with meals and should definitely drink when they're thirsty. But if you're sick, or it's warm out or you're exercising, you'll need more. Be sure to drink some extra water when you're out in warm weather, especially while playing sports or exercising. When you drink is also important. If you're going to sports practice, a game, or just working out or playing hard, drink water before, during, and after playing. Don't forget your water bottle. You can't play your best when you're thinking about how thirsty you are! When your body doesn't have enough water, that's called being dehydrated. Dehydration also can keep you from being as fast and as sharp as you'd like to be. A bad case of dehydration can make you sick. So keep that water bottle handy when the weather warms up! Not only does water fight dehydration, but it's refreshing and has no calories. Your body regulates the amount of water in your system. The body holds on to water when you don't have enough or gets rid of it if you have too much. If your pee is very light yellow, you are well hydrated. When your pee is very dark yellow, it's probably time to drink up. You can help your body by drinking when you're thirsty and drinking extra water when you exercise and when it's warm out. Your body will be able to do all of its wonderful, waterful jobs and you'll feel great! Back to Articles Related Articles Dehydration Our bodies need water to work properly. Find out more in this article for kids. Read More What's Sweat? Everybody sweats. Find out why perspiration happens in this article for kids. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.