How to Purify Water in the Wild With 2 Water Bottles.





Introduction: How to Purify Water in the Wild With 2 Water Bottles.

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In this instructable, I will show you how to purify abit of water when you are in the wild and trying to survive with 2 water bottles.

Step 1: Things You Need

You need 2 water bottles. (If you find any in the wild)
Some duct tape or masking tape ( always carry some in any kind of outdoor trip)
Some dirty water or urine (really!)
Alot of sunlight

Step 2: Step 1

First take 1 bottle and fill it up with dirty water. Make sure that it does not leak outside the opening of the bottle when on its side.

Step 3: Step 2

Tape the other bottle to the opening of each other. Make sure that none of the contaminated water or liquid flows or leaks into the empty bottle.

Step 4: Step 3

Place the taped bottles in a area where sunlight is always shinning. Place the 2 bottles at a leveled area where there no slopes or leveled ground. EDIT: Sometimes you want to place the clean bottle abit upward so the evaporation can collect more better. But just a little bit so the purified water doesn't drain back to the dirty bottle.

Step 5: Step 4

Wait for most of the water to evaporate into the other bottle. (This might take more then 12 hours)

Step 6: Enjoy!

Carefully cut open or peel open the tape and drink the fresh water in the bottle that does not have the contaminated liquid.

Step 7: Wondering How This Works?

Wondering how this works? Well....the contaminated water will go into evaporation because of the sun, the evaporated water will collect in the other bottle giving you fresh water.

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    You may not know this, but you can simply filter the water if it is murky. Then place the plastic bottle in the sun after you take to label off. Place it on a rock for eight hours. The ultra violet light will kill most all bacteria. Water in a zip lock bag will work too.

    1 reply

    Actually, only 6 hours of direct sunlight is required.

    I just thought of a great addition to the survival kit: get a small plastic Freznel lens--they are now available very cheaply on-line--get the kind that spreads the light a bit rather than focusing it, and you can heat up your water, or cook food, especially if combined with aluminum foil for extra solar reflection. You do need some sunlight for this method to work. Be careful not to burn yourself!

    With the flames of a fire to sterilize the bottles it can be done. People get the wrong idea to a certain point. When they see films of actors putting knifes in the fire to use for surgery etc. And its glowing hot.. its mostly cauterizing. To stop bleeding and kill bacteria. When running the blade through the fire can still kill bacteria. Same with the plastic bottle. But really you can't disinfect inside the bottle with the flames. It won't work.

    great idea, but too risky to a you really have to be careful not to cross contaminate the clean water. One drop of contaminated water can cause the user alot of harm. As over 1000 bacteria can be transfered.

    This should work - it's evaporation/condensation. Though I think you're better off digging a water pit and using a tarp, but this should work too. If you can somehow set the source water on a hot rock and get some stream water over the collection bottle, that would work even better.

    How do you clean the bottle that you drink from?

    10 replies

    usually people throw away bottles with the caps on. So the inside should be clean. But if you can only find a dirty bottle, then sterilize the bottle by using heat over a fire.

    Heating a bottle over a fire will melt the bottle before the usual bacteria are roasted. Also, if you have a bottle that can resist enough heat to kill bacteria, why not just put water in there and boil it? Much faster than waiting for the sun to evaporate it.

    Actually most bacteria are destroyed at lower temperatures than required to melt a PET bottle (270C) or even distort it (~80C) in fact they use thick PET milk bottles in Germany and heat sterilize them - same for some baby bottles. Even the UV in sunlight will kill some bacteria.

    Nevertheless the point made elsewhere that if you have a source of heat to evaporate the water is a valid one, much quicker than the Sun. I think though that if you were dying of thirst you would risk a few of someones bacteria. (Probably safer than a kiss.) Or you could discard the first collection.

    What worries me is why the water would selectively condense in the clean bottle. The primary bottle would always be cooler because of evaporation. I would cover the contaminated bottle with something black and cover the clean bottle with a wet cloth or wet soil (wet with contaminated water would do). In the wind this would evaporate and cool the clean bottle.

    A tried and true trick is to cover a small container of dirty water standing in a bowl with a closed cylinder cut from a plastic bottle. Standing in the sun; the water condenses on the plastic and runs down into the bowl. This can be tuned with bits of damp cloth to be quite efficient.  Except for the bowl you can make this all from one 2 liter bottle.  Obviously several of these would be required to keep a person alive. 

    hmmm, why would the water vapor go to the clean bottle & not stay in the dirty bottle...hmmm... I've been thinking about this. Maybe because as liquid water turns into water vapor, latent heat energy is absorbed in the water vapor, cooling the surround air (including the air in the clean bottle). Since most of the heat energy is now in the vapor, the clean bottle is now probably a little cooler and enough to start a natural air circulation cycle of hot area to cold area. The water vapor now condenses on the slightly cooler, clean bottle. From a weather science article, "When water changes to a phase with less energy, such as vapor condensing into water drops, the water gives off the extra energy - called latent heat - to it's surroundings. When water changes into a phase with more energy, such as raindrops evaporating into water vapor, it draws heat from it's surroundings and cools." A perfect example is the cooling effect of perspiration, because liquid water turning into water vapor carries heat energy with it and we feel cooler.

    the water condenses in both it just evens out, and you can slightly tilt the bottle to collect more evaporation

    Cooooool! I shall remember that trick, and will amaze my friends with it the next time we go camping.


    Well, most people don't think the trip will turn into a mess. So people don't usealy bring a flint or even have one for starting a fire. How many people do you know that know how to start a fire with just wood, a shoelace, and a rock? Not much. Im just saying that many people don't know how to start fires or have a flint. So this would work well too.

    i know how to start fires and i have a flint...

    Well, seeing as I am in a Scouting group... I was just commenting on your previous comment about using a fire to sterilize the bottle. Since a person is using fire to sterilize the bottle, I just assumed he or she had fire to boil water with.

    But won't the sun rays hitting the receiving plastic bottle infect it from the the plastic itself? You should've thought about that before posting genius!

    2 replies

    Actually the sun won't "Infect" anything there Hambone. Over time (A long time) it will breakdown the integrity of the bottle, but that is of little concern when you are trying to survive. The only misstep in this Instructable is reminding all involved to properly disinfect the area wear tainted water came in contact with the mouthpiece or screwtop of the potable water. As microbes can linger and be consumed from simple contact. Great instructable. Thanks for the tip.

    That was really rude you saw that he was just a kid...