Humans can live for weeks and sometimes months without food. Going without water, however, is a different story…

Two-thirds of the human body (by weight) consists of water. Humans need water for circulation, respiration, and converting food to energy. After oxygen, water is the body’s most important nutrient. Quite simply, you need water to live.

Your body loses water constantly through sweat, urine, and even breathing. You must replace the water your body loses for your organs to continue to work properly. Dehydration occurs when your body doesn’t have enough water, because you’re losing more water than you’re taking in.

In extreme heat, an adult can lose almost half-a-gallon of water through sweat alone. Without water, dehydration can set in within an hour in severe heat. The combination of physical overexertion and extreme heat — without water — can lead to death in as little as several hours.

Surprisingly, it’s also easy to become dehydrated in very cold environments. Since cold air cannot hold much moisture, it dehydrates your body with every breath you take. Even if you aren’t sweating, you still need to replenish fluids even in cold weather.

So how long can you survive without water? Humans in average shape and perfect conditions (not too hot or cold) can probably live for three to five days without any water if they’re not physically exerting themselves. Healthier people can live a day or so longer, while those who are unhealthy or exposed to particularly hot or cold weather may not survive as long.

To stay healthy, you need to continually replenish your fluid supply. Experts recommend drinking approximately two quarts (64 ounces or about eight glasses) of water each day. Of course, if you live in an extremely hot or cold area — or if you exercise a lot — you may need to drink a gallon or more of water every day.

If you love animals, you may already know that camels are famous for being able to go long periods of time — in the desert heat — without drinking. Camels in the Sahara Desert have been known to survive six months or more without drinking during the winter. In the extreme heat of a desert summer, they can still go five to ten days without drinking.

So how do they do it? Some people believe it’s because they store water in the humps on their back, but that’s not true. Their humps are filled with fat, which allows them to go a long time without food.

Camels can go a long time without drinking because their internal body temperature can vary much more than a human’s, which allows them to withstand high temperatures without needing to sweat to cool their bodies. Camels also have specially-shaped elliptical blood cells, which promote blood flow and don’t allow blood volume to drop when fluid levels drop. These factors allow them to survive in harsh desert climates without water for days at a time.

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  1. The 64 oz a day thing is a myth. You don’t need nearly that much. It comes from a misunderstanding of some research in the 50s, which said you need that much to process your food intake each day. But you get most of that from the food itself.

    • Thanks so much for visiting Wonderopolis and for sharing your beliefs on how much water a person needs to survive, d_senti! We appreciate your opinion! :-)

    • Hello, Weasle! Thanks for letting us know you liked the camel in the video for this Wonder! We think it’s super cute, too! :-)

  2. Did not know that camels store fat in their humps instead of water. The reason they can go so long is because their body temperature and the shape of their blood cells!

    Caleb’s Creek Elem.

    • Hi there, Wonder Friends at Caleb’s Creek Elementary! We are so glad you’re WONDERing with us today– camels are super cool! We think it’s really interesting to learn how certain animals stay healthy and store food– everyone is different! Thanks for sharing your comment with us, we’re glad you’re here! :)

  3. i thought that the hump was for water but now I stand corrected. However I think I heard about this before but eh. Otherwise, now I know how much water you need.

    • Great work, Tyler J! We are proud of you for learning something new about water intake! It’s important to stay hydrated! We Wonder if you have any Wonders of your own to share? :)

  4. I don’t think this answers the question (at least mine). 8 glasses of water is the ideal and the amount for one to consume to stay healthy. The question though, has the word “survive”. What’s the amount of water does an average size adult person really need to take just to survive. NOT STAY HEALTHY but just to NOT DIE in a tight situation, like for example he’s lost in the jungle and just hanging in there to live.

    • We appreciate you comment, Chuck! You make a great point– it’s idea to take in water each and every day, but what if that wasn’t the option? According to many researchers, humans can go three to five days without water intake and survive. However, we do not recommend attempting this– water is an important part of life and health! It depends on the climate, conditions and seasons. All these factors can change how little water your body can take in order to survive. We would love to hear about what you’ve found on your own, too! :)

  5. I really appreciate you guys replying on my comment. Well, I found out that an average adult, doing average activities (walking, making fire etc.) and on a regular climate should at least consume 2 pints of water a day to sustain life for at least a couple of weeks (just to buy time until help arrives). Although obviously, this is not just an unhealthy practice but really dangerous, 2 pints of water a day can be the difference between life and death in a situation. Thanks again. You have an awesome website. Please email me for anything. I love facts, trivia and important information.

    • WOW, thanks for sharing all the great research and information you found, Chuck! What a great Wonder Friend you are! Thanks for visiting Wonderopolis, we’re so glad you’re here! :)

  6. I enjoyed this article, and I, too, thought camels stored water in their humps! But I was looking for the same thing as Chuck. I am storing water, but wondering what the least amount per day (not just for 3-5 days but for maybe a month) would it take to sustain life… I appreciate the site and also, thanks to Chuck as well.

    • Thanks for sharing what you learned from our water Wonder, Phyllis! We’re glad you are here today and you’ve been asking even more questions! Keep up the awesome WONDERing! :)

    • Hey there, Wonder Friend Candace! Thanks for WONDERing about H2O with us today! We learned that drinking 64 ounces of water each day is a great way to stay healthy, but we can go quite a few days without water (but we wouldn’t want to try it ourselves)! Each and every person is different, so it’s difficult to say exactly how much water we need… it less than a gallon a day! :)

    • Alright, we love your enthusiasm, Ruben! Thanks for WONDERing about water with us! We sure do need water to keep our bodies and minds healthy! We hope you’ll keep WONDERing with us! :)

    • WOOHOO for WONDERing, Madison! Thanks for telling us that you have enjoyed WONDERing today! When you’re thirsty, what is your favorite thing to drink? :)

    • What an awesome question, Wonder Friend! We DO NOT recommend drinking dirty water at any time – even if you’re desperate. Dirty water can lead to lots of stomach issues and we want you to be healthy! :)

    • Hi MIss Berg, great point! Water is very important no matter what the temperature! We’re so glad you learned something new with us today and we sure hope you’ll visit us again soon! :)

  7. Wow these camels must be able to last without food for a long time because those humps are big and apparently store lots of fat so that they can live without food for a while!

    • You are absolutely correct, Wonder Friend B! Camels are incredible animals and they are able to store food and water for a long time. It helps them travel without having to stop and look for nutrients! :)

      • Hi Grant, thanks so much for sharing your comment! We’re thrilled that you and your son have been WONDERing together about clean water. Good luck with your project, Wonder Friend! :)

    • How WONDERful, Ana! It is sad to think that so many people have to live without clean drinking water. Thanks for WONDERing with us! :-)

  8. All that is so not true and are mere assumptions without further investigation, humans can live up to 14 days without water, I personally stay 10 days without food and water to test this theory and I am alive and healthy, and camels store fat not water yes but their body combines fat which is created by hydrogen atoms with oxygen the camel breaths, tada! IH2o the body ofthe camel creates its own water for survival from fat, and from their fat lump, temperature theory you say is contradictory on everything you say about water being essential even on any weather, please do real investigation before posting and ruining information.

    • Oh no, Aly! Please do not try testing this theory out on yourself. It is best to stay well hydrated everyday in order to remain healthy. Thank you for sharing your thoughts with us today!

    • Thanks WONDERing with us again today, sian pi. We’re SO HAPPY you commented and shared your learning with us! We hope you join us again tomorrow! :)

  9. I did know that you needed water to survive, but I did not know that even when you are not sweating that you needed water.

    • That’s AWESOME that you learned something new today, Amaria! Thanks for spending time WONDERing with us about water today! :)

  10. You need lots of water to survive. According to my surviving research, you should drink a lot of water but not too water. Right?

    • Hey there, Larry! Yes, you need water for survival, but too much could be harmful. Thanks for visiting Wonderopolis today! :)

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Have you ever wondered…

  • How much water do you need to survive?
  • How much water should you drink each day?
  • How do camels go so long without drinking?

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Try It Out

Ready to dive deeper into water today? No need for a swimsuit! All you need is your imagination and a friend or family member to help you explore one or more of the following activities!

  • Ever wonder about the water that pours out of your tap at home? Take a virtual tour of a water treatment plant to learn about how safe drinking water is treated and delivered to your home. If you can, plan a trip to your local water department to learn more about exactly how your tap water at home gets from its source to your sink!
  • What would you do if your water was determined to be unsafe? Occasionally, cities will issue “boil orders” when they determine that a problem exists with drinking water. When this happens, you need to boil the water that comes out of your tap before it is safe to drink. But how long do you need to boil it? Although you may hear many opinions on how long you need to boil your water, the correct answer is zero minutes. That’s right! In the time it takes your water to reach the boiling point, all impurities will have been removed.
  • Check out the Environmental Protection Agency’s Water Filtration activity. You’ll learn all about the water filtration process and even how to make your very own water filter!

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Have you ever wondered what path the water that flows from your tap at home follows? Explore National Geographic Xpeditions’ Splish, Splash: Water’s Journey to My Glass lesson to learn more about the hydrologic cycle and water’s journey to your glass.

 

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