Practical Survival Skills 101 - Water

In this continuation of our series on practical survival, we’re going to discuss water: where to find it and what to do with it to make it "safe."

Water is a common theme in survival - it is unique in that it is both an absolute necessity and a looming threat at the same time. Behind breathable oxygen, it is the single most important element on our survival saw, and we have just three days to ensure a clean, potable supply of water if we are to survive. This is an overview of the “hard” way of procuring safe drinking water. Obviously, Katadyne filters, iodine tablets, and other methods of purification are superior, when they are available. However, we can’t always count on technology, and so here we’ll talk about how to strain impurities/debris and kill microbes in the water.

When determining how we’ll come by water, there are several things to consider:

Demand - How many people are you providing for?

Source - Where will you get the water?

Collection - How will you collect it?

Decontamination - How will you make it safe to drink?

Obviously, some common sense needs to be applied here:

  • Don’t contaminate water. Build latrines at least 100 feet from your water source.
  • Stagnant water must always be purified.
  • Keep water resources separate - douse water, cleaning water, and drinking water should all be separated.
  • Use only what you need - keep stocks proportional: drinking water is always the priority.

When assessing the demand for water, figure that each person requires about three gallons per day in order to take care of hygiene and replenishment. Also, consider that this is the bare minimum - in austere conditions, this requirement may well exceed 5 gallons.

So, it’s imperative that you assess this as a part of your initial assessment when you choose a site (we'll discuss this in greater depth in the MAP-E assessment within the next Practical Survival 101 post, which will focus on Shelter)

Once you understand the logistical demand your party will have for water, you can begin considering what to do to procure it. Keep in mind, you’ll need to rinse any cookware, clean your hands after using the restroom, and may want to use some to wash your face, feet and other areas that are prone to bacterial buildup


Your water source will depend greatly on a variety of things: Your location, rainfall, demand, and duration of stay. Obviously, if you’re only going to be in a spot for a night or so, you do not want to create a splendid purification system that cannot be taken with you.

This is what lightweight, portable filters are for! Pick one up to get you where you’re going, and then apply these principles.


Water collection in most areas is relatively easy - things as simple as rain barrels or as complex as cisterns can be used. Water is difficult to transport, but it’s very important that your plans and equipment reflect the need to have some at hand. Personally, I carry 3 water containers:

  1. A 3 liter Source bladder in my backpack (3rd Line)
  2. An 8 oz. canteen with metal cup in my backpack that can be moved to my belt if needed (3rd/1st Line)
  3. A 24 oz. water bottle in my everyday carry bag (2nd Line)

Over the years, I’ve encountered a lot of people who decided that they really only need one of the above, usually a Camelbak or similar piece of equipment that holds a good amount of water and makes drinking it convenient. This approach begs the question - how will you refill it? If you’re on the move, how will you collect and purify water with only one reservoir?

This is my logic behind carrying the canteen and cup - strained water can be taken from the collection device, put in the cup for boiling, and then added to the canteen, bladder, or bottle. A note on bottles and canteens - dummy cord them to your backpack. Murphy’s law - if it can get lost, it will.


This process can be drawn out and difficult - there are numerous ways to decontaminate water, and experts show a range of different ways. My approach is a simple, effective method that will work with almost any size container and can be constructed simply and without many tools. Sound easy? It is. This is the “street fight” version of water purification - simple, effective, and meant to stop the crisis.

First things first - what you’ll need:

  1. A container through which to strain the water
  2. A cloth to put over the top of the straining bottle
  3. Sand and charcoal, in equal amounts, to fill the straining bottle
  4. A knife to puncture the bottom of the straining bottle and cut open the top
  5. A receptacle in which the strained water can be boiled

It’s important to remember that the straining container can be anything - a milk jug, a coffee cup or can, a five gallon jug or a 55 gallon jug - whatever you happen to have available. The more savvy you become, the more things like bark will start looking like a reasonable straining device.

Step One

Find a suitable container - in this instance, I’m using a milk jug because my batteries went dead at the camp-site. The process is effectively the same, though I will have to cut some corners. I’ve taken a half gallon milk jug and perforated the cap with about 16 small holes, and cut the bottom so as to form a ‘flap’ - I’ve perforated this flap twice, and will use zip ties to hang it from a fence upside down, so when I put the water in, it will pass through the filtering material (sand and charcoal) and the particulates in the water will be filtered.

The cap - half finished:

The flap - again, this is deceptive. I wouldn’t have it this high off the ground because of the risk of the flap tearing off. Assess these risks when you practice this problem:

And passing the water through - make sure you get rid of the plastic debris that comes off the cap (or aluminium, or whatever)

These pictures are very deceptive - this was a off-the-cuff reproduction, and I didn’t have time to go search for sand or charcoal during this exercise. That said, a little dirt, ash, fine gravel and cloth is all you need - combining a porous material such as cloth or charcoal with a grainy one such as sand or dirt will help get the particulates out.

Once this is accomplished, we’ve got to worry about the bacteria that could be contaminating the water.

Step Two

Strain the water through a cloth - a lot of people have taken to carrying scarves or a shemagh these days, and those make good items through which to strain the water into the cleaning receptacle. Once you’ve done that, allow the water to trickle through and collect in a cup that can be used to boil the water - for me, this is my canteen cup.

Step Three

Now you’ve got the larger things (larvae, algae, bugs, dirt, etc) filtered out, it’s time to address the microbes. Simply put - you need to boil the water. No shortcuts, you have to get your fire going, and have a container you can set on the coals until it’s at a lightly rolling boil for 10 minutes. It takes patience, but so does diarrhea - take your pick which you’d prefer. At this point, we’re trying to get rid of the bacteria that are going to cause infections and sickness. This is really a case of preventative medicine. Be very cautious about what you drink and eat - when you’re in the wild, think of your water as you would meat - cook it.

Water purification is not exciting. It’s an ongoing process that needs to occur right along site improvement to make sure that your party has a source of good, clean water with which to drink, cook and maintain hygiene. A small cookpot is a handy thing to carry, as it’ll allow you to clean more water (though it takes a bit longer to get boiling) so consider your needs, your area and your approach - then practice.



This new What Should I Do? blog series is intended to surface knowledge and perspective useful to preparing for a future defined by Peak Oil.  The content is written by readers and is based in their own experiences in putting into practice many of the ideas exchanged on this site.  If there are topics you'd like to see featured here, or if you have interest in contributing a post in a relevant area of your expertise, please indicate so in our Input on the What Should I Do? Series feedback forum.

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This series is a companion to this site's free What Should I Do? Guide, which provides guidance from Chris and the staff on specific strategies, products, and services that individuals should consider in their preparations.  

This is a companion discussion topic for the original entry at

Thank you Aaron.
I really appreciate these pieces!

Thanks for sharing your knowledge in this area with us, Aaron;  I’m looking forward to the rest of your series!

AaronThanks for a good practical survival summary. 
We all think about the “big” things, but a simple way to have water to stay alive may well be the most important of them all when push comes to shove

Very nice Aaron.  I’m thinking what might be of particular use is an example of how this could be ‘scaled up’ on short notice… I’m just thinking that it’s inevitable that if we’re procuring drinkable water in this fashion when at home, we will probably find a lot of neighbors desperate for drinkable water.  Being able to help one’s neighbors get drinkable water may prove to be a lifesaver, and not just for them (healthy neighbors helps make for a more secure neighborhood).  I know many people have bought or built their own large-scale water purification and filtering setups, but I would like to see how it would be done with stuff lying around the house and finding our inner MacGyver.
I’m thinking perhaps using a series of 5-gallon buckets (55-gallon drums may work too but may be rather unwieldy) and large soup pots with homemade rocket stoves might be one approach.  Heaven knows I’ve got enough buckets, empty and full Cool.

  • Nickbert

Excellent article Aaron.  A wonderful lesson in simplicity and “usin’ the 'ol noggin”.

Thank you as always for your generous contribution.

I have a couple of questions.  If you have time I would be very grateful for your thoughts:

  1. Does it matter what order the cloth, gravel, dirt, etc. are layered?  How deep should it be?  I assume and inch or so would be adequate to get the particulates out.

  2. Those zip ties look incredibly useful for multiple purposes; Is that a standard thing to carry around in a BOB?  Seems like a cheap handy way to bind things together. I guess this is more of a statement than a question but thought it was interesting. I intend to get some for my pack.


Much appreciated


yes, excellent post Aaron- you are a wealth of practical info.  love the simple, non-proprietary ingredients- so appropriate for when SHTF.  I always knew that sand and charcoal are the best filters, but didn’t understand that it was really that simple, thought it had to be processed somehow.
re-charcoal:  how does one make it?  is it really as simple as saving the blackened, crunchy bits of partly burned wood out of a fire?  I always worried that they themselves would produce tiny particulates which become even harder to filter out- and wouldn’t that be carcinogenic?

edit- never mind, it is easy enough to google- turns out I was just being oblivious/lazy.

Dr. Martenson,
Thank you for the kind words - it’s my pleasure. 
I view these as “small” issues that orbit the much larger issues you highlight in the crash course.
Hopefully, people can use these primers to manipulate the tides, to continue the orbital metaphor.

Pinecarr, Osb,

Thank you sincerely for the kind words!  


Most definately - I started with Fire, because in the progression, fire is a very important part of the water purification process. Not only does it boil the water itself, but it provides you with one of the key ingredients.


I agree -the best way to survive is to understand the concepts, and have the ability to adapt them to your particular needs. While a 55 gallon drum might seem fairly unreasonable (and I haven’t done it myself) the concept doesn’t change. This is the “consistency across categories” approach, to borrow from Martial Artist Marc Denny. 
With simple, consistent techniques, we can work quickly towards goals. I believe strongly that the fight for survival is essentially the same, regardless if it’s a physical altercation, or a process of dealing with resources.

We have to Observe, Orient, Decide and Act -  commonly known as the “OODA” loop - this is a concept I plan on getting into futher in later additions to this series and the security series that’s “in the works”.


Yes! I apologize for not being more clear, both with my words and graphic depictions - I’m planning on getting back out and getting some better pictures. The Cloth should be the first and last thing that the water touches - Therefore, I tend to put it over the bottom spigot, and rest the cloth over the side until I’ve layered the Charcoal and Sand.
As to the depth of the sand/charcoal, it varies on several things: 

  1. The size of the container, and;
  2. The amount of water being purified, and;
  3. The initial state of the water (how putrid or clean it is) 

I’m not sure if there is a specific rule for this, but I just try and stay consistent - Ultimately, this process is a bit redundant. That said, if I were trying to purify marshy pond water, I’d spend a bit more time on all steps in this process, just to be sure.


Thank you kindly - I appreciate it. You’re right with your google search - it’s actually very easy.

The thing about these skills is that they are the types of things anyone can do to “harden” their baseline readiness. Surviving with convenience is easy enough, but surviving when things get rough required an ordered mind, some experience and a systemic threat/solution analysis that anyone can do.

I’ve always hated the approach of many experts that this stuff is reserved only for the elite outdoorsman or professional. In my experience, sloth follows accomplishment. Always learn!

Cheers, and thank you all!