Picture of How to purify your water
When you find yourself an a survival situation, you do not always have access to chemicals or a filter to purify the water so you can drink it.

You could just boil the water but this would n't get sand and other particles out of the water and the chemicals will also remain in the water after cooking it. Which in turn could affect your health.

So the best way to purify your water is to use a filter.
Often you can build a water filter with the resources you have available, this gets the particules, dirt and some of the chemicals out of the water.

It is wise to boil the water after you filtered it so that all bacteria and viruses are killed.
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Step 1: The Filter

Picture of The Filter
A water filter can be created by removing the bottom of a bottle. Turn the bottle upsidedown (with the cap down down).
and put the following materials in the bottle.
- pebbles
- Sand
- a piece of cloth or bandages
- charcoal
- a piece of cloth or bandages
- Sand
- pebbles

The cloth or bandages are used to ensure that all the different materials do not mix.
The pebbels and sand filter the particules and the dirt out of the water.
The charcoal gets a big portion of the chemicals out of the water, but it won't get it all out. (You can use charcoal from your campfire).
This filter will not remove any viruses and bacteria from the water so you have to boil the water after it is filtered.

Step 2: How to use your filter

Picture of How to use your filter
Gently scoop some water from a puddle or a pond with your cup, try to get as little dirt as possible into the cup. The more dirt comes along with the water the faster the filter becomes clogged and can no longer be used.

Pour the water from the pool or pond in top of your water filter, catch the water at the bottom of the filter in a clean cup.
it is best to throw away the first bit of water that comes out of your filter it often is cloudy and not that clean.

If the water that comes out of your filter is clear it is good and you can use it.

Boil the water at least 1 minute before drinking it, cooking will kill bacteria and viruses that are still present in your water.

If you put some spruce needles in the boiling water, you'll also have a tasty tea.
MeganE16 days ago

Thanks for these instructions! There are tons of different ways to purify water. One of the most common is just to boil it. Boiling isn't always possible, though. I really like the idea of making a purifier out of a water bottle. I'm totally going to give this a try.

DoloresB17 days ago

There are a lot of different ways to purify water, and this one definitely works. Personally, I think I would rather boil the water. In an in home situation I would just install a water purification filter. It kind of just depends on what you are talking about.

kz4402 years ago
I am curious about the flavor of the filtered water. I recently moved into a house that has terrible tasting water. I do NOT want to pay the high price of water service, not even my dogs care for the water. The water is safe enough but has a high calcium content and tastes salty. I can't even handle coffee made from it. Any clues as to the flavor change?

Charcoal filters remove chlorine which accounts for a lot of the bad taste. It will not remove salts though. Minerals pass right through the filter. But the chlorine in your water bonds to the carbon in the charcoal so that taste and odor is removed.

elkliko (author)  kz4402 years ago
I can't say alot about the flavor of the water because the water i use isn't that bad i only have to remove the dirt, bacteria en chemicals that are in the water, I do not think that it wil get the salt out of sea water for instants. but you can always try it because the ilter is very easy and cheap to make.

In your case it can help to vaporize your water and than condence it again.
When you boil salt water the salt in the water won't evaporate and you can get rid of the salty tast, but as you can imagine this is a intensive way of cleaning your water and i don't know if it wil get rid of calcium.
kz440 elkliko2 years ago
...actually, it's not salt water... it has a slightly salty taste though. I am going to try the filter, but perhaps on a larger scale as I have to have water for my spoiled dogs, but hey- they don't like this water either.

Thanks for your reply, much appreciated.

ercela312 months ago
I was wondering if you acn use any sand and if you can buy active charcoal?
Jared1012 months ago
Very helpful
KesateB2 months ago

From my understanding and i have done not alot but a fair bit about filtration and purification processes research, have gone to talk to a few water filtration companies local in my country and here is their expertise advice. ( Please be advised to always ALWAYS do your own research into water purification and disinfection methods before testing what you might propose to do) Boiling water at a normal altitude will kill most viruses and bacteria, once it hits to a rolling boil ( you will notice that the water looks like it is rolling like a micro wave on the shoreline of the sea or lake) let it continue for at least a minute, anymore will evaporate the water ( Particularly if you are in a scarce water area such as when Bushcrafting or trekking, hiking etc , but will not remove chemicals and heavy metals residues and the such, still great if your only fears of the source water is pathogens and viruses, effective if you have background knowledge of the water source in question ( In higher or mountainous regions, a rolling boil will take longer as water boils at a different temperature depending on altitude). Activated carbon setups ( There are various designs based on a simple principle, to absorb/attract and/or energise is what i was told by one expert, the chemicals and residues towards the charcoal. Other mediums used in the processes are to aid turbidity, taste, sediment separation among others.

Hope it helps guys and gals!

Brown Hick

Croocket5 months ago

Hi! Thanks for a great instructable. I have a question about the longevity of the filter; how much water could you filter before having to change the charcoal? I'm guessing it gets less effective after a while?

Momo55566 months ago

if you can I need it quick thanks!

elkliko (author)  Momo55566 months ago
you asked how this works well in the simple way:
the chemicals bind with the charcoal and with that they are filtered out of the water and get stuck in your filter.
amethena1 year ago
dose any one no what chemicals it takes out
Momo5556 amethena6 months ago

no sorry

Momo55566 months ago

how dose that work? I'm doing a protect and would like to know thanks!

I always carry water.
Cedar tea will stave off scurvy.

Not a bad article.
A coffee filter can filter out debris nicely.
A good source for activated charcoal is aquarium filters.

How to make Activated Charcoal would be good also.
Take wood, paper, or bone, you can even use nutshells or corn husks.
Seal it in an airtight container.
A glass jar with a tin lid will enable you to watch as the material changes to activated charcoal.
Poke a vent hole in the lid and heat over a fire.
The smoke and hot gasses will escape out the vent hole leaving behind the activated charcoal.
Let cool slowly if you use a glass jar or the glass may shatter.
Ok so what exactly is activated charcoal and how is it different than regular charred wood? why is activated charcoal used for filters? I need to understand!
Charred wood like from a bonfire is exposed to the air when it is burned and it has the chance to absorb carbon dioxide and other contaminants as it burns. Charred wood does not always burn through to the center.

Activated charcoal used for filters is burned in a container that does not allow air into the container to contaminate the carbon with carbon dioxide or other contaminants. It is pure carbon for a better term.

Activated charcoal used for filters, absorb carbon dioxide and other contaminants, this wont happen if it is already contaminated.

Actually, various sites I was just reading before I came to here, said that activated charcole is charcole that has been treated with oxygen to increase its pouros suface area to maximize absorbtion.

Activated charcoal is made a number of different ways I was just giving one example.

AH! I get it. Thank you josehf. Makes perfect sense.
dealowis2 years ago
this simple way is helping me. i use this as a experiment in school, my teachers all love it. they ask: who created this purifying water way? i answer: Elkliko who that made it!!
so thanks for the tips :)
elkliko (author)  dealowis2 years ago
Nice to hear that you used this Instructable as an experiment, if you want to make it even more natural you can make a funnal from birchbark instead of using a bottle.
chiefredelk2 years ago
Water filters can be VERY important even to those people with city water may need one....

Sometimes our city water stinks and taste's like Chlorine and is almost impossible to drink.

I've had to add Hydrogen Peroxide to my water just to get it down. Boiling it did not help much...I plan on making a filter like this one but using a 5 gallon bucket. instead. ALSO.. I am thinking of pouring something through it FIRST to kill any bacteria that may be living in the filter...Since our water is safe to drink I do not want to add bacteria to my end product in the filtering process.. I would think a small amount of house hold bleach poured through the filter then flushed out with fresh tap water may work but to much at one time may soak into the charcoal and ruin it's effectiveness.. Does anyone have a better idea ?. Also IF I make a filter how often should I need to toss the sand and charcoal out and replace it with fresh..? Can you go by taste ? OR is there a tell tell by looks ?
Schmidty162 years ago
um kz i can help u with ur problem i will get back to u tomrrow but u can have like a big metal 55 gammion drum and have i mounted of a five or heat source and have copper tubing leading out of it and it will condense when it gets come i may wriit up a dizine but u will nee a way to cool down the steam to condense it back in to purfied water the u will have ur good coffie
Obviously this method is not very effective. True, it will remove large dirt and rock particles but what is the point of this when you can just use a thin wire mesh and take away the particles. After that you just boil the water without the hassle of building a complex and space consuming object.
Do you really think that a simple "thin wire mesh" filter is the same as charcoal, pebbles sand AND mesh?
Hi voyageur10,
it is true that charcoal and all that would be a lot better if you did not heat the water as it would remove some chemicals whereas the wire mesh would not. But when you boil the water you are removing the chemicals and killing the germs anyway.
Not necessarily will remove all chemicals (boiling). In some cases might concentrate them.
elkliko (author)  evasiveJ4v3L1n3 years ago
The diference between this water filter and a thin wire mesh is that it wil get a big portion of chemical out of the water that would not hev been filtered with a thin wire mesh. That is why i prefer to filter the water with a filter instead of a mesh.
hbueso3 years ago
Distillation removes some contaminants, carbon filter others. I would first filter the dirty water for solids then, carbon filter it, distillation and carbon filter again. Plenty of info. on this on the internet. Research water purification methods and find which methods reduce or eliminate what chemicals and use them in conjunction with one another.
triumphman3 years ago
Excellent 'ible! Thanks for the survival tips! Water is the essence of life! Without it there would be nothing but dust on earth.
CrLz3 years ago
Nice filter, simple enough to do on the fly while outdoors.
I know who's cup and hand that is!!! BEAR!
This is useful, thanks! We included it in a round up of appropriate technology Instructables on our site. You can see the post here.
funke753 years ago
I would think you would need to boil the water longer than a minute. I thought 10 was the minimum.
elkliko (author)  funke753 years ago
Nope 1 minute will kill most bacteria and virus in you're purified water.
zazenergy3 years ago
Good survival tips. Makes me think I should never leave home without a fresh supply of water!