Four Ways to Make Salt Water Drinkable

PDF download Download Article
Desalination methods for science projects or wilderness survival
PDF download Download Article

Desalination is the process of removing salt from saltwater, which might be necessary due to a lack of clean drinking water in your area. You might also need to do this someday if you are ever stranded somewhere without access to salt-free water. There are several ways of removing salt from water and turning it into drinking water.

How to Make Ocean Water Drinkable

Fill a large pot with salt water and place a boil-safe cup in the center of the pot. Place the pot lid upside-down on top of the pot, then bring the water to a slow boil. Let the water simmer for 10–15 minutes, then let it cool for about 30 minutes. Taste the water that’s gathered in the cup—it should be fresh!

Section 1 of 4:

Turning Salt Water Into Drinking Water with a Pot and Stove

PDF download Download Article
  1. Use a heat-resistant cup that is short enough that you can still put it inside of the pot with the lid upside-down on top of it. Make sure the cup doesn’t touch the pot lid or the fresh water may not be able to enter the cup. [1]
    • A Pyrex or metal cup is safest. Certain types of glass will explode when exposed to heat, and plastic may melt or deform.
    • If you don’t have a pot with a lid that will work, you can use aluminum foil instead.
  2. Do not overfill the pot—stop well before the water level has reached the mouth of the cup. This will help to ensure that no saltwater splashes into the cup while the water is boiling. [2]
    • If any saltwater gets into the cup, your newly made fresh water will be contaminated.
    Advertisement
  3. This will allow the purified water vapor to drip into the drinking cup as it condenses. Position the pot lid so that the highest point or handle of the lid is facing down towards the cup, directly above it. [3]
    • If you’re using foil, seal the edges tightly but leave a little slack in the top so the foil dips down in the center.
    • Make sure the pot lid has a good seal with the edges of the pot. Without a good seal, a lot of the steam will escape, reducing the amount of fresh water you can catch.
  4. Use low heat to boil the water slowly. If the water comes up to a full rolling boil, saltwater might splash into the fresh water glass. Let the pot simmer for about 10–15 minutes—be careful not to let the water boil off all the way, as it could damage the pot. [4]
    • If you’re using a pot with a clear lid, you’ll be able to see the condensation gathering on the glass as the water simmers.
    • After enough vapor collects on the lid or foil, the droplets will run down to the lowest point in the center of the lid, then drip into the cup.
  5. The cup and water will be very hot, so let it sit for about 30 minutes before you take the cup out of the pot. There may be a small amount of saltwater left in the pot, so be careful not to splash any saltwater into the fresh water when you’re removing the cup. [5]
    • The cup could still be a little warm after 30 minutes, but it should be cool enough to safely handle.
    • Taste the water in the cup—it shouldn’t be salty at all! The purified water vapor will collect in the cup, leaving the salt in the water remaining in the pot.
    6. Advertisement
Section 2 of 4:

Solar Desalination Using Two Containers and Plastic Wrap

PDF download Download Article
  1. Only fill the container up with about 1 in (2.5 cm) of water—don't fill it up all the way. Leave some space at the top of the bowl so that the saltwater doesn't splash into your freshwater receptacle. [6]
    • Make sure your bowl or container is watertight. If it is leaking, your saltwater will drain away before it can form steam to condense as freshwater.
    • Start this project early on a sunny day—solar desalination takes several hours.
  2. Do this carefully so no saltwater splashes into the new container, which would contaminate your freshwater as you collect it. [7]
    • For your new container, use a cup or a smaller bowl—any container will work as long it’s watertight and the rim is above the level of the salt water.
    • You might need to weigh the new container down with a rock to prevent it from sliding around. Alternatively, you can press a small circle of clay into the bottom of the first container and put the new container on top of the clay to hold it in place. [8]
  3. The wrap should be loose enough that it has a little give, but tight enough that it doesn’t touch the water or cover the top of the second container. Seal the plastic wrap tightly around the rim of the saltwater bowl. If there are any leaks in the plastic wrap, steam or freshwater vapor might escape. [9]
    • Using heavy-duty plastic wra p will help keep it from tearing.
    • Make sure the second container is directly in the center of the first container before you put on the plastic wrap.
  4. Do this just above the cup or container in the center of the bowl. This will cause the plastic wrap to dip in the center, creating a sort of spout so fresh water will drip into the second cup. [10]
    • Don’t use a heavy rock or weight that is so heavy it will tear the plastic wrap.
  5. The heat from the sub will cause condensation to form on the plastic wrap. As condensation forms, freshwater droplets will slowly drip from the plastic wrap and into the cup. [11]
    • This method takes several hours—be patient.
    • After you have enough fresh water in your cup, you can drink it. It is safe and completely salt-free.
    6. Advertisement
Section 3 of 4:

Making a Solar Still from a Plastic Bottle

PDF download Download Article
  1. 1
    Find a large plastic bottle and a smaller container that can fit inside it. If you find yourself needing drinking water on a seashore, you may be able to turn seawater into fresh water using materials you find on the ground nearby. First, look for a relatively large plastic bottle, like a large water or soda container. Then, find another, smaller container, like a smaller plastic bottle or an aluminum soda can. [12]
    • The smaller container needs to be able to sit inside the first container.
    • Make sure the larger container has a lid—if the top is open, the salt water will just evaporate away.
  2. 2
    Cut the top off of the smaller container to make a cup. This will be the container you use to hold your seawater. Be careful with this part—the edges of the can or bottle will be very sharp after you cut them. [13]
    • If you’re a kid, have a grown-up help you with the cutting.
  3. 3
    Cut the bottom off of the larger container and fold it in. Carefully cut away the bottom of the larger plastic bottle. Then, tuck the cut bottom edge of the plastic bottle inside the rest of the bottle to create a lip or basin along the inside of the bottle. [14]
    • The lip is where your drinking water will collect.
  4. 4
    Put a cup of salt water inside the larger container and place it in the sun. Fill your makeshift cup with seawater, then slide the larger container over the saltwater cup. Use sand, rocks, or sticks to hold the containers steady, and place them in a sunny spot. [15]
  5. 5
    Drink the fresh water in the lip. As the sun heats the water, it will evaporate, and the water vapor will start to gather on the sides of the larger container. Eventually, it will run down into the lip you created. [16]
    • When you’ve collected enough water, carefully remove the lid from the larger bottle and take a drink.
    6. Advertisement
Section 4 of 4:

Turn Seawater to Fresh Using a Life Raft

PDF download Download Article
  1. Remove the gas bottle from the raft and open it to let out the gas. Put a piece of cloth over the opening of the bottle, then pour salt water through the cloth until the bottle is nearly full. The cloth will filter the seawater so you don't get too much sand or other debris in the water. [17]
    • Don't overfill the bottle to avoid spilling the water.
    • This method is most helpful if you are stranded on a beach with no fresh water. It was developed by a stranded pilot during WWII in the Pacific.
  2. Pull the hose off of the bellows and place it against the opening of the gas bottle. Wrap the leak stoppers around the hose and mouth of the bottle to create a strong seal. [18]
    • Make sure the hose isn’t kinked, twisted, or clogged, or the water won’t be able to travel through it.
    • If you have any twine or tape, you can reinforce the seal with these items.
  3. 3
    Put the free end of the hose into a fresh water container. Use a bottle or can that you find on the beach to collect your fresh water. Make sure the hose is securely inside the container—if it falls out, your fresh water could spill into the sand. [19]
    • It may help to bury the middle section of the hose under the sand—this will cool the water vapor as it travels down the hose, helping it turn back into water.
  4. Eventually, the water will start to boil. The steam will go into the hose, leaving behind salt and other impurities. As it condenses again, it will start to trickle into the bottle or can you’re using to collect the fresh water. [20]
    • Once you have enough water in the bottle or can, taste it—it shouldn’t taste salty at all!
    5. Advertisement

Expert Q&A

Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Video

      Tips

      • Solar methods take a longer period of time and might not be adequate for making lots of freshwater quickly, but it’s a fun experiment, and could be useful in true survival situations.
        Thanks
        Helpful 0 Not Helpful 0
      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Name
      Please provide your name and last initial
      Submit
      Thanks for submitting a tip for review!
      Advertisement

      You Might Also Like

      4 Ways to Purify Water for Drinking, Cooking, and Sanitation
      How to
      Boil Water (& How Long It Takes)
      How to
      Save Water at Home: 17 Expert-Backed Ways
      How to
      Make Distilled Water
      How to
      Adjust Water pH
      How to
      Check Your Water Quality with or without a Kit
      How to
      Boil or Treat Contaminated Drinking Water
      How to
      Test Water Purity
      How to
      Check Water for Fluoride
      How to
      Collect Rainwater for Drinking
      How to
      Find Drinking Water in the Desert
      How to
      Filter Water
      How to
      Make a Water Still
      Do You Have Rusty Water? Causes, Fixes and Safety Issues
      Advertisement

      References

      1. ↑ https://greensborosciencecenter.wordpress.com/2020/08/18/diy-science-desalination-experiment/
      2. ↑ https://greensborosciencecenter.wordpress.com/2020/08/18/diy-science-desalination-experiment/
      3. ↑ https://greensborosciencecenter.wordpress.com/2020/08/18/diy-science-desalination-experiment/
      4. ↑ https://greensborosciencecenter.wordpress.com/2020/08/18/diy-science-desalination-experiment/
      5. ↑ https://greensborosciencecenter.wordpress.com/2020/08/18/diy-science-desalination-experiment/
      6. ↑ https://www.education.com/download-pdf/activity/17479/
      7. ↑ https://www.education.com/download-pdf/activity/17479/
      8. ↑ https://www.education.com/download-pdf/activity/17479/
      9. ↑ https://www.education.com/download-pdf/activity/17479/
      1. ↑ https://www.history.navy.mil/content/dam/museums/undersea/education/Sea+Water+to+Fresh+Water+Desalination.pdf
      2. ↑ https://www.history.navy.mil/content/dam/museums/undersea/education/Sea+Water+to+Fresh+Water+Desalination.pdf
      3. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      4. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      5. ↑ https://www.youtube.com/shorts/kteQRjDoNTA?t=5&feature=share
      6. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      7. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      8. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      9. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      10. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/
      11. ↑ https://survival-kompass.de/en/remove-salt-from-water-for-drinking-water/

      About This Article

      Article Summary X

      To turn saltwater into drinking water, start by pouring the saltwater into a bowl and placing a small cup in the center of the water. Then, cover the bowl with plastic wrap and set a rock on top of the plastic wrap over the cup, which will make a dip so fresh water can drip into the cup. Next, put the bowl of saltwater in direct sunlight. As the saltwater heats up in the sun, condensation droplets will form on the plastic wrap, and freshwater will drip into the cup in the center of the bowl. For tips on turning saltwater into drinking water using a stove, keep reading!

      Did this summary help you?
      In other languages
      Thanks to all authors for creating a page that has been read 2,213,222 times.

      Reader Success Stories

      • Ava Clark

        Sep 27, 2017

        "This article helped me understand ways on how you can turn salt water into fresh drinking water It came to my mind ..." more
        Rated this article:
      More reader stories Hide reader stories
      Share your story
      If you buy through links on our site, we may earn a commission .

      Did this article help you?

      Advertisement