What Are the Best Low-Tech Ways to Desalinate Water.
Imagine Being Surrounded by Water You Can’t Drink…
Picture this: you’re stranded on a sun-baked coastline, endless blue waves crashing at your feet, but not a drop to drink. Or maybe you’re deep in the backcountry, your canteen empty, and the only water source is a salty tidal creek. What would you do. Sure, modern desalination plants can turn entire oceans drinkable—but what about when you’re off the grid, far from high-tech solutions.
You’re not alone in wondering. Water scarcity affects nearly 2. 2 billion people worldwide, according to the World Health Organization. That’s almost one in three people who don’t have safely managed drinking water at home. And since around 97% of Earth’s water is salty, knowing how to turn saltwater into freshwater with simple, low-tech tools could literally be a lifesaver.
In this series, I’ll break down the best low-tech methods you can use to desalinate water—whether you’re a prepper, an outdoor adventurer, or just curious about survival know-how. In Part 1, we’ll talk about why desalination is so important, especially off the grid, and dive into one of the most accessible methods: solar desalination. Ready to learn how to transform the undrinkable into the essential. Let’s get started.
Why Desalination Matters – Especially Off the Grid
Before we get our hands salty, let’s talk about why desalination is such a big deal. Water scarcity isn’t just a faraway problem; it’s a growing global crisis. The United Nations estimates that by 2025, nearly two-thirds of the world’s population could be living under “water-stressed” conditions. And while high-tech desalination plants in places like the Middle East are producing millions of gallons of fresh water every day, those systems require massive infrastructure, electricity, and tons of money.
But what about those times when you’re nowhere near a plant—when you’re camping, sailing, or facing an emergency. That’s where low-tech desalination methods come in. They don’t require fancy gadgets or access to the grid. You just need basic supplies and a bit of know-how.
There are plenty of real-world examples of these simple techniques making all the difference. In 2012, for instance, a group of fishermen survived 28 days adrift in the Pacific by using makeshift solar stills (more on those soon) to capture drinkable water from seawater and even their own breath. And in disaster-stricken areas, humanitarian organizations often turn to solar distillation kits to bring safe water to remote communities.
The bottom line. Low-tech desalination isn’t just a “nice-to-know” skill—it’s a potential game changer in survival, travel, and preparedness scenarios.
Solar Desalination – Harnessing the Sun
Let’s talk about arguably the most accessible method: solar desalination.
If you’ve ever seen water droplets on the underside of a plastic lid or window, you’ve witnessed the science behind it—evaporation and condensation. The beauty of a solar still is that it uses the sun’s energy, which is totally free, to separate water from salt and other impurities.
How Does a Solar Still Work.
Here’s the simple science:
- Evaporation: The sun heats up salty or dirty water, turning it into vapor (but leaving the salt and contaminants behind).
- Condensation: The vapor cools against a surface (like plastic or glass), forming pure water droplets that you can collect.
What Do You Need.
You don’t need much for a basic solar still:
- A clear plastic sheet or bag (even a large Ziploc will do)
- A container (cup, bowl, or even a depression in the ground)
- Something to weigh down the plastic (a small rock works)
- Sunlight, and a little patience
Step-by-Step: Building a Simple Solar Still
In-Ground Solar Still:
- Dig a bowl-shaped hole in the ground, about 2-3 feet wide and 1 foot deep.
- Place a container at the center to collect fresh water.
- Put salty or dirty water (or even damp plant material) around the container.
- Cover the hole with clear plastic, securing the edges with rocks or dirt.
- Place a small rock in the center of the plastic, directly above the container, so the plastic slopes downwards.
- As the sun heats the pit, water evaporates and condenses on the underside of the plastic, dripping into your container.
Above-Ground Solar Still:
No shovel. You can drape a clear plastic bag over leafy branches, seal it, and let the sun do the work. The leaves “sweat” moisture, which condenses inside the bag for you to collect.
Solar Still Pros, Cons, and Tips
Pros:
- Uses free solar energy
- Purifies both salt and dirty water
- Low-cost and easy to build
Cons:
- Slow process—on a sunny day, expect about 0. 5 liters per day from a basic solar still
- Requires steady sunlight and patience
- Yields might be too low for large groups or extreme conditions
Tips to Increase Yield:
- Use the biggest plastic sheet you can find
- Add more wet plant material or salty water for more vapor
- Make sure the plastic is sealed tightly around the edges to prevent vapor loss
A 2018 study found that the efficiency of a homemade solar still can range from 30-50%, depending on weather and construction. Not bad, considering you’re harnessing just sun and a few scraps.
Ready to try solar desalination for yourself. Up next, I’ll
dive into another classic approach that just might be sitting in your kitchen already: boiling and condensation—better known as simple DIY distillation.
Boiling and Condensation – Simple DIY Distillation
If you can boil water, you can distill it—and in the process, remove salt and most impurities, making even seawater safe to drink. This method dates back centuries and is still used by survivalists, homesteaders, and sailors around the world when the chips are down.
The Basic Principle
Distillation works thanks to a simple scientific fact: when you boil saltwater, the water vapor that rises carries only pure H₂O molecules; the salt and other minerals are left behind. If you collect and cool this vapor so it condenses back into liquid, you’ve got drinkable freshwater.
Setting Up a Makeshift Distiller
You don’t need specialized equipment to get started. Here’s an easy way to set up a basic distillation system using what you’d find in most kitchens or camping kits:
You’ll need:
- Two pots (one smaller than the other, so it can sit inside without touching the bottom)
- A heat source (campfire, stove)
- A lid (preferably glass or metal with a handle in the center)
- Ice or cold rag (to speed up condensation on the lid)
How to do it:
- Pour the saltwater into the larger pot, then place the empty smaller pot inside, making sure no salty water gets in it.
- Invert the lid and place it on top of the large pot so the handle points down over the small pot (this way, the condensed droplets will drip into your collection pot).
- Place ice or a cold rag on top of the lid to encourage condensation.
- Gently heat the saltwater to a simmer—not a hard boil—to avoid splashing salty water into your catch pot.
- As the water boils, vapor rises, condenses on the cool lid, and drips into the small pot.
Safety Note: Be careful when handling hot pots and steam. Always use oven mitts or thick cloth to protect your hands.
When Is DIY Distillation Useful.
Distillation is a solid backup plan if you have access to fire or a camp stove but no clean water. It’s especially handy in survival scenarios where you can improvise with available materials. Plus, it’s great for purifying most types of contaminated water—not just salty, but also muddy or biologically unsafe sources (though keep in mind it won’t remove all chemical contaminants).
Real Life Example:
During the aftermath of Hurricane Dorian in the Bahamas, residents used improvised stovetop distillers to purify brackish floodwater when bottled water ran out. It’s a time-tested trick that still saves lives today.
Downsides:
- Fuel intensive: Requires a steady heat source.
- Slow: Typically yields 0. 5–1 liter per hour depending on setup.
- Not super portable for long-distance treks but ideal for camp or home base emergencies.
Alternative Low-Tech Methods to Try
While solar stills and distillation are the go-tos, there are a few other creative, low-tech desalination hacks worth knowing—especially if you’re stuck without plastic or pots.
1. The Freezing Method
This one can be surprisingly effective if you’re in a cold climate. When saltwater freezes, the ice that forms first is mostly fresh water; salt gets pushed out of the forming ice structure. By carefully harvesting the newly-formed ice and letting it melt, you can get drinkable water. Limitations: Not practical for survival unless you have freezing temperatures, and the process is slow. But it’s been used in polar expeditions for over a century.
2. Clay Pot and Evaporation
Ancient civilizations, like the Greeks and Persians, used specially designed clay pots to gradually desalinate water through evaporation and re-condensation. While you probably won’t have a “desalination amphora” on hand, experimenting with clay pottery can mimic this effect on a tiny scale.
3. Homemade Membrane Filters
Some have tried using layers of cloth, sand, and charcoal to “filter” salt out of seawater. Unfortunately, these don’t remove dissolved salt—only dirt and some microbes. The only real way to separate salt is through distillation, evaporation, or freezing.
4. Plastic Bottle Condensers
If you have a couple of clean plastic bottles, you can set up a mini “condensation train. ” Fill one bottle with saltwater, connect it to an empty bottle, and leave them in the sun with the empty bottle slightly elevated. As water vapor travels and condenses in the cool bottle, you collect small but vital drops of salt-free water.
5. Community Solutions: Warka Water Tower
Some villages in Ethiopia use structures like the Warka Water Tower, which condenses water from humid air using nothing but natural temperature changes and local materials. While not a desalination solution per se, it’s proof that low-tech water collection can change lives in arid regions.
By the Numbers: Desalination and Water Scarcity
Let’s look at just how important these methods can be, and how they stack up:
- Only about 2. 5% of Earth’s water is freshwater—and less than 1% is accessible for human use (UN Water).
- 97% of the world’s water is salty and undrinkable without some form of desalination.
- Solar stills yield about 0. 5 liters per day per square meter of plastic, according to field studies.
- DIY distillation setups can produce approximately 0. 7–1 liter per hour, but require a continuous heat source.
- On
Part 3: Fun Facts, Expert Insights, and What’s Next
As we wrap up Part 2, we’ve uncovered classic low-tech desalination tricks—from harnessing the sun’s power with a solar still to using basic kitchen gear for DIY distillation. We’ve even explored some creative hacks for the resourceful and desperate alike. But desalination isn’t just a matter of survival; it’s a fascinating blend of science, history, and human ingenuity. In this part, let’s dive into some fun facts you might not know about low-tech desalination—and meet an inspiring expert who’s spreading water wisdom worldwide.
Fun Facts: 10 Surprising Truths About Low-Tech Desalination
- Solar Stills Mimic Rain Clouds
The science behind a simple solar still is the same process that makes rain: evaporation and condensation. In fact, your backyard solar still is a mini water cycle in action.
- Clay Pots Were The First Desalination Tools
Ancient Greeks and Persians crafted clay vessels to separate salt from seawater over 2,000 years ago. These rudimentary stills inspired many modern designs.
- You Can Use a Car Windshield as a Solar Still
Stranded at sea or in a remote area with a vehicle. Some shipwreck survivors have used car windshields to catch and condense freshwater from saltwater using the sun.
- Distillation Removes More Than Salt
Not only does distillation eliminate salt, but it also purifies water from many bacteria, viruses, and heavy metals—making it one of the safest ways to make water drinkable in emergencies.
- Plastic Bottle Hack: Even Kids Can Try It
A two-bottle solar distiller can be built as a science project—no fire required. It’s a favorite with teachers to explain the water cycle and safe water concepts.
- Rainwater Harvesting Isn’t True Desalination
Catching rain is a great survival skill, but it’s not technically desalination. However, many indigenous communities combine rainwater harvesting with basic distillation in dry seasons.
- Freeze Desalination is Used in Arctic Expeditions
Polar explorers have relied on slow freeze-desalination—skimming fresh ice off frozen seawater for a precious drink. It’s slow but crucial in freezing climates.
- The World’s Smallest Solar Still Can Fit in Your Pocket
Some emergency kits include a foldable plastic sheet solar still that weighs less than 50 grams—small enough to keep in your hiking pack just in case.
- Freshwater Yield is Modest—So Use Water Wisely
A one-square-meter solar still may only provide half a liter per day, so rationing and combining methods are key in survival.
- Desalination Research is Inspiring New Inventions
Ongoing studies into low-tech desalination have led to modern reinventions, such as solar-powered “hydropanels” and improved ceramic filters—bringing hope to dry regions worldwide.
Author Spotlight: Meet Cody Lundin, Survival Water Guru
No discussion of low-tech desalination and survival water wisdom would be complete without mentioning Cody Lundin. A renowned survival instructor, author, and co-star of Discovery’s “Dual Survival,” Lundin is famous for teaching practical, no-nonsense skills that anyone can use in the wild or at home.
Cody’s book, 98. 6 Degrees: The Art of Keeping Your Ass Alive, features clear, step-by-step guides to building solar stills, boiling water safely, and finding creative ways to stay hydrated when resources are limited. He’s a vocal advocate for learning “primitive” skills—not just for emergencies, but to foster a deeper respect for nature and self-reliance.
What sets Lundin apart is his hands-on approach: he regularly tests desalination techniques in real-world conditions, using only what you’d likely have on a hiking trip or in your car. He debunks myths (no, drinking seawater is NOT safe. ) and encourages experimentation—urging everyone from kids to seasoned preppers to try making a solar still in their backyard.
If you’re looking for inspiration and reliable advice, be sure to check out Cody’s work—his books and YouTube channel are packed with easy-to-follow demonstrations and survival wisdom.
What’s Next. Your Low-Tech Desalination FAQs
So now you know the basics, the alternatives, and some surprising facts about low-tech desalination. But what about the questions that come up when you’re actually trying these methods—like “Is it safe. ” or “How much water can I really get. ” In the final part of this series, we’ll answer the most common and crucial FAQ about low-tech desalination, so you can be prepared for any situation.
Ready to demystify the details and get expert-backed answers. Head to Part 4: Your Low-Tech Desalination Questions—Answered.
Low-Tech Desalination FAQ: Your Top Questions Answered
Now that you’ve explored the science, history, and hands-on methods behind low-tech desalination, you might still have some practical questions. That’s normal. It’s one thing to know the theory, but another to actually create safe drinking water when you need it most. Here are the ten most common and important questions about low-tech desalination—answered clearly and simply, so you can be ready for any situation.
1. What’s the absolute simplest way to desalinate water without special equipment.
The classic solar still is your best bet if you’re stranded with almost nothing. All you need is a clear plastic sheet, a container, and sunlight. Dig a hole, place a container in the center, pour salty water around it, cover with plastic, and weigh down the center. As the sun heats the saltwater, fresh vapor condenses on the plastic and drips into the container.
No pots or stoves required.
2. How much fresh water can I realistically get from a solar still each day.
Yields depend on sunlight, temperature, and still size. A typical one-square-meter solar still can produce about half a liter (500mL) per day—sometimes more in hot, sunny climates. It’s not a ton, but it can be enough to help keep dehydration at bay, especially if you combine with other water sources or methods.
3. Can I distill water using kitchen pots if I have a fire or stove.
Absolutely. Place salty water in a large pot, set a smaller pot inside to catch the drips, and invert the lid so condensation runs to the center and falls into the small pot. Add ice or a wet rag on top to boost condensation. This method purifies water quickly if you have fuel—just be careful to avoid burns and don’t splash saltwater into your collection pot.
4. Does distillation remove EVERYTHING harmful from water.
Distillation removes salt, most bacteria, viruses, and many heavy metals. However, some chemicals or volatile organic compounds (like gasoline) can vaporize and re-condense with the water. So, only distill water from sources free of chemical contaminants. For the most part, distillation is one of the safest low-tech ways to get drinkable water.
As the Bible says, “He makes me to lie down in green pastures; He leads me beside the still waters. He restores my soul. ” (Psalm 23:2-3 NKJV)—wise guidance not only for our spirits, but for seeking life-sustaining water, too.
5. What about using homemade filters—can cloth, charcoal, or sand remove salt from water.
No. While homemade filters can remove dirt, debris, and some pathogens, they cannot remove dissolved salt. To actually desalinate, you need a method that separates pure water from salt at the molecular level—like distillation, solar stills, or freeze desalination.
6. Is the freezing method practical for most people.
It’s only practical in freezing climates, like during winter or polar expeditions. When salty water freezes, the first ice is mostly fresh—skim and melt it for drinking. It’s slow and not suitable for most survival situations, but it’s a neat scientific hack if you’re ever in the Arctic.
7. Can you desalinate water with just plastic bottles.
Yes. Connect two plastic bottles (one with saltwater, one empty), place the saltwater bottle in the sun and the empty one in the shade or ice. The vapor travels and condenses in the empty bottle as fresh water. It’s slow and yields small amounts, but it could save your life in a pinch.
8. Are there portable, low-tech desalination kits I can buy.
Yes—there are compact, foldable solar stills and emergency distilleries that fit into a backpack. While not always cheap, they’re designed for hikers, sailors, and emergency preppers. Just search for “emergency solar still” or “portable distiller” online.
9. How can I maximize water yield with basic materials.
- Use the largest clear plastic sheet or surface possible for a solar still.
- Add more saltwater or damp plant material around your collection cup.
- Seal edges tightly to prevent vapor loss.
- Build multiple stills if you have enough material—more area equals more water.
- For stovetop distillation, use a lid with a steep angle and keep the heat low to avoid splashing.
10. What are the biggest mistakes to avoid with low-tech desalination.
- Drinking saltwater directly—this will make dehydration worse.
- Letting salty water splash into the collection pot during distillation.
- Using contaminated water with unknown chemicals—distillation won’t remove all toxins.
- Poorly sealed solar stills—lost vapor means lost fresh water.
- Not allowing enough time—all these methods are slow, so plan ahead.
Wrapping Up: Why Low-Tech Desalination Matters
We’ve journeyed through the basics, the how-tos, and even some wild survival hacks for desalinating water without electricity or heavy machinery. Whether you use a solar still, a DIY distiller, the freezing method in arctic climes, or even clever plastic bottle hacks, the message is clear: with just a bit of resourcefulness and know-how, you can turn undrinkable water into life-saving hydration.
Remember, as highlighted by survival expert Cody Lundin, mastering low-tech desalination isn’t just about emergencies—it’s about self-reliance, respect for nature, and being prepared for.