Over the year i have been researching where to find water in an emergency situation or just when being out in nature taking a hike through the landscape. While it is probably safe to drink water in nature in places like Canada, Norway, Sweden, Finland, eastern parts of Russia, Alaska and pretty much everywhere on earth that is far away from industries, the quality of water within these places still varies a bit, but they are still better off than third world countries where environmentalism has not been prevalent in politics. Depending on where you are you may get lucky drinking unpurified water, but you may also end up dead as the result of drinking contaminated water because you did not pay attention.
The purpose of this document is not to scare you off any products or make you drink only bottled mineral water, the purpose of this document is to make you aware of the risks associated with each type of water purification and give you information on how to purify water.
There is one simple rule you need to remember: always filter - always boil. Filtering removes the bulk of he pollution you can see, boiling will kill anything you cannot see.
Water sources and their overall quality:
- Springs out of mountains/rocks
- High quality and clear water, probably directly drinkable with no filtration. Probably very rich in minerals.
- Small stream
- Good, make sure you can see water moving Moving water makes a bad breeding ground for parasites.
- Again water needs to be visibly moving as mentioned above.
- Rainwater and Snow
- Ok. Probably a bit chemically contaminated.
- Should not be your first choice, there could be run off from farmland or industry.
- Inland sea (freshwater)
- Like Lakes. Should not be your first choice.
- Open sea (bracken water, somewhat desalinated), example: sea between Sweden and Finland ("Bräckt" water in Swedish).
- According to the Swedish Army Survival Guide (Handbok överlevnad), you can drink a maximum of 0.2l per day, add some freshwater - if available. Avoid drinking this kind of water at all.
- Exception: Can be used to cook food items after boiling for a while to purify the water.
- Open sea (not desalinated)
- Undrinkable. (Requires a reverse osmosis pump to remove salt).
- Exception: Can be used to cook food items after boiling for a while to purify the water.
- Toilet water.
- Undrinkable, high probability for faecal matter containing viruses and other bad things.
What is turbidity:
Turbidity is the remains of dead lifeforms (bio-matter), dust, dirt, and sediments that makes the water murky. It is easily filtered using a bit of cloth, but filtering just turbidity does not make water safe to drink. Only boiling or high grade filtering assures its purification.
The taste of water:
Filtered water can taste bad. Some filtering devices with carbon filters removes some agents in the water that make it taste bad. Using chlorine as a purifier will give an obvious aftertaste of chlorine, it can be mitigated by adding some citrus liquid to it. Other forms of chemicals can probably result in an aftertaste as well, but i haven't found any examples of those.
Water during winter:
Water freeze from the top down. As you can guess what will probably happen to water bottles, yes, they freeze from the top and down. Carry your water bottle upside down if you are in freezing weather conditions. If you have a plastic bottle, you can keep it inside your jacket or sleeping sack, if you have a metallic bottle, you can warm it up over a heat source.
I have seen someone on youtube cooking water in a plastic bottle - so while it may work, plastic bottles do gets deformed if exposed to a fire or other heat source. Avoid boiling water in a plastic bottle unless you are desperate or there is plenty around. There is also a risk of polluting the water with plastic compounds that are set free when heated.
Eating snow is one possibility, but it will cool you down and make your body burn calories to warm up again. Try to avoid this if you are in a survival situation. If you do eat snow and get a brainfreeze, put your tounge up in your mouth so it touches the palate. I used to eat snow when i was a child going out doing long distance skiing, thinking back on it, it was a good way to cool down as i burned calories.
During the wintertime, waterfilters that are based upon hollow microfibers (Sawyer Mini, Lifestraw etc) can freeze, and when that happens the microfibers can crystallise and be destroyed. Keep the waterfilter near your body heat to prevent this from happening.
Getting water from nature:
- Moisture traps:
- Place a plastic bag around plants or tree branches with leaves, moisture will condensate and water will be collected at the lowest point in the bag. Change trees next day (trees need that water too).
- One can also place vegetation (grass, leaves, herbs, flowers etc) in a plastic bag and capture condensation. Also gathers at the lowest point in the bag.
- A more elaborate trap can be made by placing a plastic sheet over a hole in the ground that have a large plant underneath. Place cup underneath plastic and then place a stone in the middle that make the plastic go down and make moisture drip down straight into the cup.
- Condensation can also be trapped on clothes you wear. Walk through a field with tall grass in the morning after fog/mist. Wring out water from clothes after.
- Disadvantage: Slow, daytime only. Require a warm climate.
- Advantage: No effort. Water from moisture traps does not require filtering (!) - directly drinkable.
- VIDEO: "Emergency Water Source - Evaporating with a Solar Still: Survival Tip"
- Clay / Mud.
- Put clay/mud in a piece of cloth, squeeze the water out by twisting the cloth or apply pressure.
- Advantage: Most places on earth have water in ground underneath.
- Disadvantage: Not possible if ground is frozen solid. Need serious filtering since this source of water is probably very polluted with bacteria, viruses (etc).
Filtering / Purifying:
- Bottle filter (Emergency solution):
- Find a bottle. Preferably a large plastic bottle. Make sure it has an opening in the bottom and at the top. You need to pour water at the top and filtered water should come out at the bottom.
- Put down a layer of rocks in the bottom (to prevent the above layers to falling out).
- Then put a layer of sand over that.
- Now put a layer of crushed coal over that (You can find coal in a fire pit)
- Last, if you have access to moss, put a layer of that at the top. Moss absorbs chemicals.
- You can add more layers if you want to, and the order does not matter much, just make sure things do not fall out at the bottom.
- Is said to be able to filter "much of the impurities", but viruses, bacteria and parasites will not be filtered.
- Disadvantage: Slow. Not a long term or safe solution
- Advantage: Can be created "in the field" since most parts are available outdoors, makes it slightly better than unpurified water. Consider the source of the water.
- VIDEO: Survival Lily - "How To Make An Emergency Pocket Waterfilter"
- Bottle Distiller (Emergency solution):
- Take a large soda bottle cut the bottom out. Fold in 1/3 of the bottle into itself.
- Take a smaller soda bottle, cut the head off.
- Put bad water into the small bottle and insert it into the larger one from underneath where the larger one was cut. Place in sunlight and the bad water will evaporate and condensate inside the larger bottle and condensate on the sides and gather where you folded the larger bottle into itself.
- Wait for a while and you'll have pure water to drink. Make several of these distillers since this takes a long time.
- Disadvantage: Slow. Requires a warm climate. Hard to fold bottle into itself without damaging it (causing it to leak, breaking the bottle).
- Advantage: Can be created if plastic trash is available - or if you have bottles with you. Removes salt from water (desalination).
- VIDEO: Dual Survival (Discovery) "How to Desalinate Water on a Desert Island"
- Reverse osmosis pumps.
- This is basically a product that can desalinate water and create drinkable water at sea. Not an option unless you can find parts to it - and know how to build it. Was featured in the movie "Waterworld" and is sometimes part of survival boats for long time sea survival.
- Disadvantage: Not that common, hard to build from scrap materials.
- Advantage: Removes salt from sea water (desalination).
- Chlorine, Hydrogen Peroxide (etc).
- Chlorine is known to leave an aftertaste, adding a citrus tasting liquid masks this taste according to some people.
- Can cause some unwanted chemical biproducts depending on chemicals.
- Variations of cryptosporidium are highly resistant to chlorine. http://aem.asm.org/content/56/5/1423.long
- Disadvantage: Slow, can take a few hours for chemicals to mix and be effective. Requires a cannister or a plastic bag, and also proper proportions to avoid poisoning yourself. Over time bad for your health unless properly mixed into water so it's not a long term solution. Horribly painful death if tablets are ingested, need to be kept away from immature or suicidal people.
- Advantage: Weighs little. Small plastic bag with chemicals (solid tablets) can me carried in your wallet.
- UV Light "pocket purification gadgets"
- This is a gimmick product sold to rip people off, Does not work - at all.
- Real industrial UV purification plants requires massive amounts of energy for germicidal purification. A toy with a battery in it cannot deliver this UV-C radiation in the same amounts to purify water through germicide.
- According to a document i read about UV purification: DNA of broken up viruses remain in the water and "can affect humans negatively", this is why the water is also filtered after the UV process, like with proper filter based on activated charcoal on an industrial scale.
- So, it still requires filtering of turbidity before and micro filtering afterwards. Pretty much pointless for survival purposes. Avoid and forget about this for the time being unless some technological revolution occur.
- US Army tested UV purification (Steripen) and the results were unsatisfactory, see page 16 (25 in PDF) http://www.dtic.mil/dtic/tr/fulltext/u2/a449339.pdf
individual water purifiers, page 16, about the Steripen UV "purifier".
- Cloth (Rough filter)
- Can be used to filter turbidity and some rough impurities out of the water. Just place a piece of cloth over a container and pour water through it. Simple as that.
- Disadvantage: Wont filter viruses, bacteria or parasites - Boil it!
- Advantage: Fast. Only requires a piece cloth - you're probably wearing one.
- Cloth (Soak+Gravity filter)
(Image above: My own experiment, worked rather well, but took a long time).
- Requires 2 containers and a piece of cloth.
- Put impure water in one container, position it somehow over the other one.
- Roll up the cloth and soak it in the container with the dirty water and position the other end above the other container.
- Over time the cloth will absorb water and somewhat more pure water will end up in the other container.
- Disadvantage: Extremely slow, wont filter anything biological - Boil it afterwards.
- Advantage: Only requires a piece cloth - you're probably wearing one. Result will be better than Rough filtering with a piece of cloth.
- VIDEO: Prepperhub - "How To Make A Simple Survival Water Filter!"
- Ceramic filtering
- Find a ceramic pot and seal it (usually have a hole in the bottom).
- Pour water into it and water will filter through it given time.
- Ceramic filters are also the basis of some commercial water filters (like Catadyn Camp).
- Disadvantage: Slow, wont filter everything (not sure what it filters actually), so boil.
- Advantage: Only requires a ceramic pot, which is widely available. Commercial solutions are also available that can filter in bulk over time.
- Trees / Vines
- Birch and maple can be tapped in the late spring (just when shoots are appearing).
- Make a small hole into the tree/Vine and tap the liquid into a container below.
- Disadvantage: Need to be plugged after tapping, can damage tree if not properly restored.
- Advantage: Some trees taste sweet , can be boiled down to a sweet syrup.
- VIDEO: MCQBushcraft "Bushcraft Foraging: Tapping Silver Birch"
- Warm up the water over a fire/surface to a "rolling boil"
- After 5 minutes the water should be purified.
- Unless you have filtered the water, there can be some residual turbidity which may contain highly resistant bacteria that is protected inside dirt. Make sure to filter before boiling. Most living thing start dying at 75'C (167'F)
- Requires something to boil water in and a fire or hot surface.
- Disadvantage: Does not remove turbidity by itself. Filter before boiling - at least for better taste.
- Advantage: Filtering and boiling basically guarantee pure water. Best way to purify water, only chemicals will slip through.
- VIDEO: Paul Kirtley - "Does Boiling Always Make Water Safe To Drink?"
- Difference between Boil and Simmer
1. Filter the water. Use a piece of cloth or a filters like Catadyn/Sawyer camp filters (bulk filtering over time) - or both.
2. Boil the water over a fire for 3-5 minutes.
There is also a product called Lifesaver (not to be confused with Lifestraw), it's a bottle with a filter built in, it is said to filter everything, including viruses (but again, not chemicals). It probably works, but it is currently (2016) about 4-5 times more expensive than competing products like Lifestraw Go bottle, which does not filter viruses. Another product is Pure2Go, which is only 2x more expensive (99$ US), However, Lifesaver was created specifically for countries which are affected by bad water, like third world countries. Lifestraw is probably ok if you chose your water source carefully.
A bit on particle sizes: (1 micron = 0.001 mm, 1 nm = 0.001 micron)
Lightblue = 0.2 microns (Lifestraw)
Medium blue = 0.1 microns (Sawyer mini)
Dark blue = < 0.1 microns (Sawyer point zero2)
Cysts/Parasites: 2 to 50 microns.
Bacteria: 0.2 to 1 microns.
Viruses: 0.017 to 0.5 microns. (Smallest known is Porcine Circovirus @ 17 nm)
Very few filtering devices that claim to be safe can filter all these, most fail to filter Viruses. So, a product that claims it filters everything - it should filter down to 0.02 microns. Read on the technical specifications and read reviews before selecting a water purification product. Be sceptical. The two known viruses that are smaller than 0.02 microns (20nm) are harmless to humans.
Lifestraw has compiled an awesome PDF of what their different products filters and won't filter. It basically says: You get what you pay for, which is probably true for all manufacturers.
- Do not store water in open containers, or collect rainwater in open containers, make sure they are sealed somehow. Birds and other animals faeces can contain dangerous viruses, bacteria and parasites, like Hepatitis A, Giardia and Naglaria.
- Storing water in a freezer. Freezing water will place any lifeforms within the water in a suspended state. No growth of viruses, bacteria, parasites and algae can occur. While parasites are killed when frozen below zero for a long period of time, viruses survive when unfrozen and start infecting again. The recommendation is that you boil the water if you are going to consume it, unless you know it came from a safe water source like from your kitchen tap.
- Make sure the containers you are going to store the water in are clean and have no leftover of whatever they were used for before, like soda cans. Even if a hint of Cocacola can be a nice addition to the flavour, it really wont help if you're going to use the water to clean out a wound.
- Even if you're storing water in containers that are sealed and the water was purified when you added it to the container, after a while the water may become unhealthy to drink because of microscopic life (plankton) that grow over time while being stored. While these plankton aren't dangerous to consume in small quantities, water that has been stored for 6 months in bottles can have a significant growth of plankton, algae and other biological matter.
- Rotate water every 3-6 months. That mean emptying them out and rinsing them off with purified water to clear them out of the stored water. Leave them open so any liquids evaporate, then they are read to be used again.
- Stay away from water near farmland. Contains lots of chemicals and pesticides.
- Stay away from ditches near highways, exhausts contain heavy metals and bad chemicals, and ditches trap and concentrate these pollutants.
- When melting snow, you need more than you think since snow is mostly crystalized water and air.
- Consider inoculating yourself against Hepatitis A and B. One less contaminant to worry about.
- After purification, let the water settle for an hour or two in the container, heavier chemicals will settle at the bottom of the container, so if you then open it up and let the water run for a few seconds, the remaining water will have less chemicals in it. So, if you have a container with a tap at the bottom, just open it up and the settled chemical impurities will exit first, if you don't have such a container, you have to improvise. Below is an example of a 10L water container with a tap at the bottom which let you remove any bad things that has gathered at the bottom of the container. Just let it run for 10 seconds and any heavier chemicals will leave the container first.
10 liter container Donken Donje, available to purchase from Jula in Sweden. Check internet for local alternatives.
- Naturally occurring chemicals will vary where you are. In Sweden for example there is Uranium in the natural water, somewhat higher doses than in other parts of the world, and the level vary within countries as well. Note: You're not going to glow in the dark if you take a zip of chemically unfiltered Swedish natural water, but a lifetime of exposure to various chemicals may affect your health negatively.
There are some exceptions in which you can drink unsafe water anyway:
- If you are extremely thirsty and are in an emergency situation and you know are going to be saved in a few hours (example: someone know where you are or you have had contact with someone), you can drink most clear looking and moving water (why moving water is good is explained above), most illnesses take a few hours to days to manifest. You can experience symptoms like diarrhoea and may have to eat antibiotics for a few weeks - but you'll live.
- If you are extremely thirsty - or even dehydrated and are not sure if you are being rescued, you have to weigh the risk of developing a serious disease vs dying. Unless you can filter and boil the water to make it safe, there is always a risk. Drinking murky water or eating snow wont make drop dead, but there is a varying risk. It's your call and your life.
Finally, here are some additional resources on water filtering:
MCQBushcraft: "Bushcraft Basics Ep08: Water Contaminants & Pathogens"
MCQBushcraft: "Bushcraft Basics Ep09: Water Filtration & Disinfection"