PURIFYING WATER: “Is This Water Safe to Drink?”
That question has led to disaster for many people who were caught unprepared. Knowing how to acquire water is one thing, but what do you do to make it safe to drink? In this article, we’re going to cover some of my preferred methods for making water safe either in the field or at camp.
Before we begin I would like to clarify the differences between water filtration, purification, disinfection and distillation:
Disinfection, such as with chemical treatments or boiling, kills pathogens in the water, but it does not remove them. Nor does it remove chemical or heavy metal contamination.
Filtration removes most common pathogens and may or may not filter out heavy metals and certain chemical contaminants by the use of charcoal and micropore filters. Viruses cannot be filtered out due to their size and their ability to pass through even the tiniest filter pores.
Purification is the removal of all biological pathogens including viruses and most heavy metal contaminates.
Distillation is the process in which water is evaporated or converted to steam and recaptured.
Purification and distillation are the most effective forms of water treatment.
We will cover a sampling of techniques which range from makeshift filters to solar distillation. Just to note: I have personally researched and practiced these methods. Knowledge is important, but in my opinion, it is incomplete without experience. By putting information to practical use, you can see what really works, what won’t, and how to employ the techniques effectively.
Mini/Straw-Type Water Filters - If you have been paying attention to any of the recent survival buzz, you have undoubtedly heard of the Lifestraw by Vestergaard Frandsen or the Frontier Filter by Aquamira. Both of these tools and others like them operate on the same principle. These are enclosed filtration devices that provide protection from cryptosporidium and giardia and improve the taste of turbid water. (The Lifestraw boasts a 0.2 micron filter and is able to filter out most waterborne bacteria as well as protozoa).
To use a straw-type filter, you simply dip the pickup end into your water source and suck the water through like a straw. These filters are extremely efficient and especially hardy because there are no moving parts that can break. The primary drawback to these filters is their non-replaceable filter elements. However, with an average usage span running from about 110 liters (Frontier Filter) up to 1,000 liters (Lifestraw), and given their low relative cost, these are a lightweight and inexpensive solution to filtering drinking water while on the move.
Now if you find yourself stranded without your kit or if your kit is lost, you can still replicate (to some extent) the filtration abilities of these straw-type filters with items you might have lying around the house or work-site. All you need is:
- an 8″ length of a 1/2″ to 1 1/2″ diameter PVC or other non-toxic pipe
- some twine, zip ties, or hose clamps
- a clean sock or rag
- some peat moss
- some charcoal
STEP ONE – Thoroughly clean the piece of pipe to ensure nothing contaminates the water past the filtration elements.
STEP TWO – Wrap the bottom end of the filter with a small piece of rag and secure it with the twine, zip tie, or hose clamp.
The next step is to create the filter element inside.
STEP THREE – Stuff a piece of the rag into the pipe so that about one inch of volume is taken up at the bottom.
STEP FOUR – Add about an inch of clean sand, and then about an inch of peat moss.
STEP FIVE – This next layer is the most important. Crush up the charcoal to the consistency of very small gravel and add about 2 inches above the layer of moss. (DO NOT use commercial BBQ coals! Use either coals from a non-chemically treated wood fire or even better use some activated charcoal for fish tanks which you can find from a pet or aquarium supply store).
STEP SIX – To finish up the filter, repeat the bottom layers with one inch of peat moss, one inch of sand, and one inch of tightly stuffed cloth.
STEP SEVEN – On the top, loosely wrap the end with cloth and tie it off just like the bottom end. You want the top end to be slightly concave like a trumpet mouthpiece so that you can press your lips into it and create a good seal.
This makeshift filter uses the same process as the commercial ones. You just stick the end of the straw into your water source and suck up the water. You should make sure to suck through about a gallon or two through the straw before you swallow any of the water to ensure the filter elements settle and shed any harmful dust.
And there you have it, one makeshift water filtration straw. Mind you it’s not as pretty as the commercial product, nor does it filter out harmful particulates as effectively, but it does work. In a pinch, something like this could save your life and provide you just enough filtration to hydrate before you find a better source of water or better supplies to filter/purify water.
Also bear in mind, this filter will not have nearly the same filtration capacity as the commercial ones. If you have to use this system for an extended period, be sure to change out the peat moss and charcoal at roughly 10 gallon intervals and wash the cloth and sand in clean water and/or let them dry in direct sunlight for a few hours.
Pump-Style Filters - There are loads of different pump-style water filters out in the market today. Because of the overwhelming variety, it would take a small book to go over all of them in detail. What I’m going to do instead, for the sake of brevity, is go over my top three choices. I chose these three filters because, in my opinion, they are the easiest to pack out, the easiest to operate, and they all work exceptionally well.
Katydyn Hiker Pro - The first filter on my list of favorites is the Katydyn Hiker Pro. This filter was the first water filter I ever bought and continues to be one of my favorites. It is the lightest pump filter I own at about 3/4ths of a pound with outside dimensions of about 6.4 x 3.2 x 2.4 inches. This filter is extremely easy to pump and I can fill a two-liter bottle in about two to three minutes.
The water from this filter always tastes fresh and the filters are easy to replace. The Hiker Pro features a draw line particulate filter as well as a replaceable 0.3 micron glass-fiber element with activated charcoal. The filters will last about 1,000 liters before needing replacement.
Be careful when replacing filters though: if you use too much force, you can crack the filter body and you’ll be forced to buy a new one. Don’t ask me how I know this, my wallet can’t take it.
The Hiker Pro and its filters are extremely common and can be found at various sporting goods stores and at your favorite web retailer. Also, don’t be confused by the two different colors. The Hiker Pro previously came in a kind of blue-grey body but now come in black; filter elements work in both and other than the color, nothing is really different between the two.
MSR MINIWORKS EX Microfilter - is one of the more efficient water filters available weighing in at a pack-friendly one pound with dimensions at about 4.8 x 2.8 x 1.2 inches. It features a three-stage filtration system consisting of a particulate filter on the draw hose and a ceramic with carbon filter element.
The particulate filter ensures no large particles are drawn into the ceramic filter element while the 0.2 micron ceramic element filters out bacteria and protozoa. The carbon in the ceramic filter element then filters out much of the potential heavy metals and provides clean tasting water. These filter elements last on average about 2,000 liters, can be cleaned in the field, and are replaceable. They are also very inexpensive, which is always a huge plus in my book.
The flow rate is impressive for the size and filtration capability. I was able to fill a 2-liter bottle in about three to four minutes. Like the Katydyn Hiker Pro, the MSR Miniworks EX is carried by most sporting goods stores and popular web retailers. So finding replacement filters and parts is easy.
General Ecology First Need XL Water Purifier - I like to save the best for last. The First Need XL water purifier is by far my favorite water filtration device out on the market today. Notice how the item is designated a water purifier. That’s because unlike the previously mentioned water filters (as well as most pump-style water filtration devices), the First Need XL filters not only bacteria, cysts, and protozoa, but it also removes viruses and does so without the use of any chemicals!
This pump weighs in at about 1.3 pounds with dimensions of about 3.8 x 1.2 x 2 inches. The draw line features a micro-mesh liner for particulates just like the previous filters. The magic behind the First Need is the “Structured Matrix” filter element that traps all the contaminates and leaves nothing but pure clean tasting water.
The First Need XL has a shorter filter life at about 600 liters. However, these filters, like the MSR MINIWORKS, can be backflushed and cleaned for extended use. The flow rate with the First Need XL is slower than basic filters. It took me about five minutes to fill a 2-liter bottle. But this is a small price to pay for the peace of mind of knowing your water is completely pure and free of viruses.
Another great feature of the First Need XL is the included carrying bag that features a food-grade plastic liner and draw line adapter. The carrying bag allows you to use the pump system as a gravity filter as well! You simply hook up the filter element to the adapter on the bag, fill the bag with water, hang it up, and the filter will purify water without any pumping. This is a great option if you want to purify water at camp while you engage in other activitiess.
The price and filtration capacity of the individual filters are the main disadvantage to this system. The filters are a little pricy and a bit harder to find. I always keep a few on hand though as this is the perfect filter for natural disaster situations where water is likely to be contaminated by human or animal waste. With this filter, there is no need to worry about the potential for viral contamination through water.
The Boil - One of the simplest and easiest ways to make water clean and potable is to boil it. Boiling kills all of the pathogens in the water and render it safe to drink. You can take it a step further and distill the water which will remove all of the contaminates, chemical or biological, and yield pure water.
There is one considerable drawback with this method: you need a heat source capable of bringing water to the boiling point, enough fuel to sustain boiling, and a container suitable for boiling temperatures. Certain situations may not afford you the ability to build a fire and you may not have the equipment needed to properly and safely boil water.
Most “preppers” include a hydration source in their kit like a bladder pack or a Nalgene-style water bottle. While these hydration sources may be good for carrying water with minimal bulk or weight, they do not allow you to heat water in them. One of the easiest ways to prepare for the possibility of having to boil water is to include something like a Kleen Kanteen in your kit. Kleen Kanteens are stainless steel water bottles that can double as a boiling receptacle if the need arises. Their weight is marginally greater than Nalgene’s plastic bottles, and because they are made of common 304 Stainless steel, they are more likely to bend and bulge before they crack.
Be sure to include in your survival kit, some reliable receptacle for boiling water.
What happens when you’re stranded with nothing at all? People in survival situations and many primitive people across the world have used items from birch bark containers, large leaves like skunk cabbage leaves, and even extremely tightly woven baskets buried in sand to boil water. You typically cannot put these types of receptacles over open flame, but there is an ingenious way of making a boiling still. Once the water is trapped in these types of containers you must heat rocks in a fire. Be careful when you do this as some types of rock can splinter and shatter violently when exposed to high temperatures. Have the rocks in the fire when you start it or add them in gently before the bed of coals is fully established to mitigate this possibility. Once the rocks have become sufficiently hot (too hot to think about holding but before they glow), drop them into the water. Enough of the hot rocks can and will bring water to a boil and render it safe to use.
“I’m not living in the woods how am I going to make a fire or heat in the city when the power and gas is out?” Good question. The solution: improvise.
For fuel you can simply use wood from furniture. Clean water trumps that Ikea computer desk when it comes to priorities. You can also burn bundles of paper. Tightly rolled-up newspapers and phonebooks [yes, they still make these] make great, long-lasting logs for fires. You can make a newspaper or phonebook log two ways:
Method One – Tear the paper into small pieces and soak them in water until they become soft. Then, take the paper pulp and pile it roughly into the shape of a log (2-3 inches in diameter) onto a towel or other piece of cloth, roll the pulp in the cloth tightly and twist the ends of the towel to close them off. Keep rolling and twisting the towel until most of the water has wrung out (or until your hands can’t take it anymore). Gently unroll the towel and remove the newly formed log. Let it dry in the sun and you have yourself a reasonably long lasting source of fuel.
Method Two – This method is much easier but it does not produce as good a log as the first. Just soak sheets of paper in water until they become fairly soft. Then tightly roll them together until you get a log roughly 2-3 inches in diameter. Then tie the log with twine or string in 1 inch intervals from end to end. When the log dries it should yield a decent source of fuel for a fire.
These skills may be useful in a disaster scenario when supplies become scarce and municipal energy sources are not available. Keep them in the back of your mind when you prepare for these types of events. Whenever you burn these logs (or burn any fire for that matter) ensure you are in a well-ventilated area or outside.
The most efficient use of any fire is to ensure that your cooking or boiling container is directly over the flame without a standing medium like a grill or plate. Whenever possible, hang whatever you are heating over the fire low enough for the flames to spill slightly over the sides. This should help you make the most of the precious fuel you have.
You do not need to boil your water for an extended period of time. The amount of boil time needed is a much debated topic among survivalists and formal sources. In my personal experience, simply bringing the water to a rolling boil is sufficient, as long as the water is filtered of sediment and particulates.
If you must boil cloudy water or highly contaminated water you may want to extend this duration to about 2 minutes. It is also important that you don’t over boil water as any steam that escapes is water that you lose. Having a lid on your container will help mitigate the loss of water through steaming.
Allow water to cool before you drink it and be sure to properly store boiled water to prevent recontamination.
The best way to make water pure and safe to drink without filters or chemicals is to distill it. You can either use a fire to boil water and trap steam or you can use the sun. There are hundreds of known methods to trap steam from boiling. For simplicity’s sake we will go over my preferred method.
First, buy a second screw top for your wide mouth Kleen Kanteen. Drill a 3/4 inch hole into the screw top and insert a 4 foot length of silicon tubing. Be sure to use silicon (or equivalent) tubing which can be used for either hot or cold water. Normal PVC tubing can only withstand temperatures up to about 175 degrees. Fit a hydration bladder adapter into the other end of the tubing and hook it up to your bladder.
To distill water with this setup, simply wrap the exposed portion of tubing in a wet bandana or sock, and boil water in the Kleen Kanteen. The Kanteen should only be filled about halfway. Otherwise a good boil can cause particulate to enter the tubing. As the water boils in the Kanteen the steam condenses on the sides of the tubing and enters the bladder as water.
This method takes some practice, and remember, the longer the tubing the better. If your tubing is too short the water will not fully condense and you may damage your hydration bladder due to heat and pressure.
There are quite literally endless methods for distilling water, but the the core principals remain the same. Capture steam, allow it to condense, and catch and store the water in an appropriate receptacle. Experiment (safely) and find a method that works with the items you have lying around. Knowing how to apply this method can save your life.
Solar Still – If you do not have access to fire and fuel, you can still use solar energy to distill water. The solar still has saved many lost both in the desert and at sea. Like the other methods the concept is the same: capture water vapor and condense it.
Because sunlight does not heat water as quickly or as hot as a fire can, this process is less efficient than distillation with fire, but it is effective.
To make a solar still:
STEP ONE - Dig a pit about 3 feet in diameter
STEP TWO - Place a container in the center of the pit to capture the water
STEP THREE - At this point you have two options: 1) place pieces of non-toxic, succulent vegetation around the container or 2) pour unfiltered water or urine around the container
STEP FOUR - Once that is done you must cover the entire diameter (and about 1 foot around) of the pit with a plastic tarp. You can use opaque tarps but a clear one such as an inexpensive rain poncho works best.
STEP FIVE - Secure the tarp with stones around the perimeter of the pit
STEP SIX - Gently roll a stone into the center of the tarp create a drip-off point for the condensing water.
As the water from either the vegetation or surrounding wet earth evaporates it will condense onto the tarp and run down into the center and drip into the container, yielding distilled water. This method, as previously stated, is not very efficient and requires hot temperatures and direct sun to work.
CHEMICAL WATER TREATMENTS
The treatment of water with chemicals is nothing new to survivalism. The actual application of these treatments do require practice and experience to ensure proper disinfection of water. Also, these treatments disinfect water but they do nothing to filter out particulates or chemical contaminants. The treated water may not have anything alive that can make you sick but may still contain chemicals and contaminates that can cause you to fall ill.
Ensure that the water you use does not carry high levels of chemical contaminants when you acquire it. Additionally, carefully monitor the quantity of treatment added to your water as most of these chemical treatments can be dangerous if used in too high of a concentration.
Potassium Permanganate – This useful survival chemical can be used as a fire starter (with glycerin), a first aid treatment for minor skin conditions, and as a water treatment. Potassium Permanganate can be purchased in pill or powdered crystal form. It should be added at about 1 gram per liter of sediment-free water. Carefully add the crystals to the water and stir until they are completely dissolved. The water will turn a slight purple-pink color but it is safe to drink.
Iodine - Iodine tablets have been given to troops as early as the Vietnam conflict and their use has been documented for hundreds of years. Iodine should always be kept in a dark container as it will degrade when exposed to light.
Ideally, when using iodine, your water should be at or over 70 degrees fahrenheit. The typical dosage of iodine for water treatment is 5 drops per quart of water. If your water contains sediment, up to 10 drops is acceptable. This treatment is tricky to perfect and there are many variables that can affect iodine’s efficacy, but it is possible to yield safe drinkable water and it is a method that has been used for many years.
Chlorine (Bleach) - This is my own preferred method of chemical water treatment. I like it because bleach is cheap and easy to find and it does not degrade as quickly as iodine. In fact, chlorine treatment is how many municipal water sources are disinfected.
Using the right type of bleach is very important. Do not use any type of bleach that has “color-safe” or fragrances added. What you want is plain, old-fashioned bleach. The most common concentration of bleach found is a solution of 5-6% sodium hypochlorite.
To use bleach, add about 16 drops (.08 milliliters or .16 teaspoons) to every gallon of water being treated. Stir the bleach in or shake it in a container. At this point you must allow the bleach time to oxidize the contaminates in your water. Wait at least 30 minutes to an hour.
Once the bleach has been allowed some time to work, open the container and smell the water. There should still be a faint odor of bleach to the water. If there is no smell that means the bleach has been completely depleted by the contaminants in your water and a second treatment of the same dosage should be done. The sniff test is important to determine whether or not all the biological contaminants in the water have been oxidized and whether any unused bleach is still present. This technique can be used on cloudy or sediment-filled water but you may need to repeat the process 2-3 times for the water to pass the sniff test.
There is one catch to this procedure. Chlorine bleach does not effectively kill cryptosporidium; they are resistant to halogen type disinfection methods. Keep that in mind when you want to use this treatment for water that may be potentially contaminated by cryptosporidium.
Steripen - This is one technique that I have used and would not personally recommend. The Steripen is a UV stick light for disinfecting water. Don’t get me wrong, this is a tried and true technique and it does work. I have, on multiple occasions, successfully disinfected water with the Steripen and consumed it without ill effect. But I do not recommend it because of my experience with it.
During a hunting trip I took out my Steripen and it stopped working. At the time, I believed the batteries had died on me. The unit I had used CR123 Lithium batteries and if you don’t know already, these are not common (aside from tactical usage). Luckily for me my everyday carry flashlight contained these batteries and I always make sure to check and top off my lights before I head out anywhere. I popped these batteries into the device, but still nothing. It had broken and I had no idea until I needed it.
It was not a big deal for me at the time as I had water in my camp a few miles away. But it does illustrate the inherent fragility of electronic devices like the Steripen. The fact that it ran on batteries also irked me. What would happen if I ran out of batteries? After doing more research online I discovered my own experience was not uncommon. Numerous users complained of units breaking or failing to achieve desirable results. My experience with the Steripen was the factor that drove me to learn more sustainable and reliable ways to purify water while out in the field.
Also, UV light disinfection tools are less effective in cloudy or sediment-laced water. While it is not extremely difficult to filter most sediment out of water, it requires more time and won’t always be successful.
Having water or access to water means nothing if you cannot use it safely. By filtering, purifying, or chemically treating your water you stand a better chance at avoiding illness and staying on the move. Nothing can be more debilitating than intestinal problems in a situation that requires you be to productive or vigilant.
In this article, we covered some of the more basic techniques for making water safe to drink, but there are numerous other methods available. As with all survival preparation, knowledge is key. Not every technique will be practical, and not every piece of gear can be carried or bought. Remember, gear can fail. Chemicals can be spilled, and containers can be broken or lost during high stress situations.
Having the knowledge to make water potable is a fundamental skill for war-fighters, survivalists, and people that love to be outdoors. Additionally, as with any self-sufficiency skill, share this knowledge with those around you. The better your peers are prepared, the less chance there is of them losing their grip on civility in chaotic situations and reverting to savagery.
Never stop learning, share what you know, and always plan ahead. And of course, if you have any questions or would like clarification of any technique, feel free to drop a comment and I will try to answer. I can, at the very least, send you in the right direction. ‘Til next time, stay safe and keep moving!