Why is drinking water so important?

Water is the key to helping your body look and feel at its best. Water is found in every cell in your body. It also helps protect your joints, carry nutrients throughout your body and carry waste out of your cells.

How much water is in my body?

Look at the pictures below to learn how much water is in different parts of your body.

A graph showing how much water is in the human body and brain
A man's body has about 60% water, or a little more than half. A woman's body is about 50% water, or about half. Both men and women's brains are about 75% water, or about almost all water.








How much water should I drink every day?

How much water you drink every day depends on your age and how active you are:

  • Ages 9-12 – About 7 glasses of water a day
  • Age 13 and older – About 8 glasses of water a day

You should drink water even if you don’t feel thirsty all the time. You should also drink more water if you play sports, exercise or if it’s hot outside.

What happens if I don't drink enough water every day?

You can get dehydrated if you don’t drink enough water every day. Dehydration is when you don’t have enough water in your body.

Signs of dehydration are:

  • Headache or dizziness
  • Feeling thirsty
  • Dry mouth
  • Dark urine
  • Not urinating as much as usual
  • Feeling confused
  • Breathing slower than usual (in bad cases)

How can I drink more water?

  • Carry a reusable water bottle with you wherever you go. Fill it up whenever you pass by a water fountain, sink or water bottle station.
  • Drink sips of water during breaks in sports games.
  • Drink water after playing a sport or exercising. This can help replace the water you lost through sweat.
  • Add slices of fruit to your water for more flavor.
  • Use apps to remind you to drink water. Here are 3 free apps that we like:
    • Water Drink Reminder®. Set reminders to drink more water and enter goals for how much you want to drink every day. Track your water drinking habits and customize serving sizes based on whether you’re drinking from different water bottles and glasses.
    • HydroCoach®. Set reminders and track your progress toward your water drinking goals. This app can also be personalized based on your needs and how active you are.
    • Water Balance®. An app that shows you how much water you should drink to balance out other non-water drinks, like soda or juice.

Rev. 8/2016. Created by Cate Medeiros. Mass General for Children and Massachusetts General Hospital do not endorse any of the brands listed on this handout. This handout is intended to provide health information so that you can be better informed. It is not a substitute for medical advice and should not be used to treat any medical conditions.