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This article (*) gives a good summary of the efficiency of boiling as a method for making water safe for consumption. In particular, Table 2 provides a summary of the temperature and time required to kill various micro-organisms. A distinction should be drawn between killing all pathogens and making water safe to drink. Sterilisation of water (killing all ...


42

The EPA recommends boiling for one minute for most people, and three minutes for anyone above 5000ft or 1000m (sic) in elevation. reference - https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water That is what I have always done when backpacking. I don't boil for 10-20 minutes because it will kill my fuel supply and waste ...


41

When you're asking for the safest way to purify water, you're asking for the method that removes the most harmful stuff from the water, like bacteria, viruses and larger impurities like mud or sand. No one method is really perfect at removing everything, so I usually use a two-stage approach: Filter: If the water source is cloudy, your first step should be ...


39

How much sea water can I safely drink? = None If you drink sea water, how much fresh water do you need to drink to off set the sea water you drank? = 2.8 units of distilled water per 1 unit of sea water (to neutralize without adding hydration) The "scientific" answer to this question involves a lot of complex math, human physiology and significant ...


37

You can place an empty cup in the middle of a lightly filled bucket of sea water. You then place a plastic bag over the bucket, with a stone in the middle so it has a dip in it over the cup. The sea water evaporates, reforms on the plastic bag (without any salt in it) and then drips into the cup. Slow but far better than drinking sea water.


36

Let's do some back-of-the-envelope calculations. The specific heat of water is the amount of energy needed to raise the temperature of a particular amount of water by 1 degree C. This is 4.186 joules/gram °C (reference). To raise the temperature of 1 L of water (1000 g) by 80 degrees C (to boiling from room temperature), would be 4.186 * 1000 * 80 = 334,...


35

Boiling- 185°F (85°C) water will become sterile in minutes. Bringing the water up to boiling point will typically sterilize it. At high altitude you may need to boil for a minute. Chemical- Iodine, chlorine, and other chemicals can sterilize water. Follow directions on products specifically designed for this purpose. Typically you'll need to mix it and ...


35

Assuming you don't have a genitourinary tract infection, fresh urine should be sterile, the problem is that it is a waste product which, apart from making it not taste very nice, means that consuming it will increase the concentration of waste in your body which will require an increased volume of water to absorb and subsequently excrete, resulting in you ...


34

Dehydration will very quickly reduce your ability to undertake the activities required to survive and so finding and conserving water should be a very high priority in any survival situation. Clearly there are potential dangers associated with drinking contaminated water but these need to be weighed against the dangers of dehydration. As with most survival ...


34

Salt dissolves in water so will pass though a normal filter or cloth. You can try that with a coffee filter at home. So there's definitely an error in the article. A still (i.e. distillation apparatus, whether solar or fire-heated) is the only easily improvised way to desalinate water, but the article I read said he caught and ate fish - that will provide ...


29

Copy and paste from the answer here: Is it a good idea to drink your own urine in a survival situation (Skeptics SE)? Summary: You can do it, as a last resort, but it's dicey. The US Army doesn't think it's a good idea and lists it on its "Do NOT drink" list, stating in its Field Manual that it "contains harmful body wastes" and that it is "about 2 ...


27

The question doesn't state what geographical area it's about, and it really isn't possible to give an answer that covers everything. In this answer, I'm only going to deal with pristine backcountry areas in North America, such as the Sierra. In order to interpret the scientific evidence properly, it's necessary to understand some scientific background about ...


25

I would get a ceramic filter that is rated to remove metals like arsenic (this is a particular issue in the UK where most surface water in the wild country can harbour arsenic - but I'd rather assume all ground water to be 'tainted' than drink it and become poisoned). I've used some hand-pumped filters which can draw water from a lake or river, and filter at ...


25

There is typically no need to purify water collected from natural sources in the wilderness. For example, in a survey of 69 sites in the U.S Sierra Nevada, every site had concentrations of Giardia cysts much too low to make anyone sick.[Rockwell 2002] The perception that backcountry water is unsafe to drink without treatment is folk wisdom that is ...


24

Generally speaking, no. Arguably you should never go for out for any kind of extended exhausting activity without ensuring proper hydration, i.e. packing enough fluids at least for your immediate needs. The life straw will allow you to purify water sources you find up to a certain degree, but some concerns remain: You first need to actually find water ...


20

Urine is normally sterile (barring urinary tract infections) - so, from bacteriological stance, fresh urine isn't going to hurt. The problem is - urine is a waste product, and so is full of stuff that your body wants to be rid of. Worse, as you get more dehydrated, your body produces more concentrated urine. That said - as a short term measure to keep ...


20

Via WebMD Large amounts or long-term use of iodine are possibly unsafe. Adults should avoid prolonged use of doses higher than 1100 mcg per day (the upper tolerable limit, UL) without proper medical supervision. However I seriously question that 1100 mcg number because people in Northern Japan have been found to consume over 80,000 mcg per day due to a ...


19

Welcome back to good old chemistry class! Apologies if this gives you nightmares. First, the tablets used for water purification are not elemental iodine, but a crystal form called Tetraglycine Hydroperiodide. So there are things besides simple iodine getting into your water. More importantly however, is that many of these things, including the iodine ...


17

This article (*) gives a good summary of the efficiency of boiling as a method for making water safe for consumption. In particular, Table 2 provides a summary of the temperature and time required to kill various micro-organisms. Sterilisation of water (killing all living containments) is not necessary to make water safe to drink. For example, boiling ...


17

I think your assumptions are correct. To my knowledge in a mountain environment you are quite safe as long as you follow some simple rules, which you mostly already named: The water was not standing, i.e. it comes from a stream that is rather fast and the stream is big enough that it is not just a connection of puddles or ponds where the water rinses from ...


16

You need to distill it - I'm assuming that freezing is not an option (unless you're camping in the extreme latitudes). This is easiest, as the ice on top is almost pure water. Where you don't have a freezer available - boiling the water, capturing the steam and condensing it back to water will provide pure water.


15

If safety is your primary concern, then the only two methods can guarantee safety from major contaminants (microbial or otherwise) these are Distillation and Reverse Osmosis Distillation Boiling alone will leave most contaminants in the water, such as heavy metals, hydrocarbons, etc... multi-stage distillation will both kill pathogens and leave most ...


15

The key is to always have a trash bag. Your most reliable backwoods method for clean water is condensation, either through natural action, or via a still of some kind. The primary component of this is having large enough suitable material to make said still. If you are depending on natural action, then surface area is still key. Assuming you left your ...


15

Filter the water right away, when filling the bottle. This way I'm sure the water inside the bottle is safe for drinking. This. Why? The main point for me is accessibility of that water. If you come to a situation where you need fresh water, then it may not just be because you've set up camp, you've got a while to spare and you feel like a drink. It may be ...


14

THE official information can be found on the CDC webpage. The CDC defines the problem in terms of what you're trying to kill: Protozoa, Bacteria, or Viruses. They address each of those in terms of water treatment methods: Boiling, Filtering, Chemical Disinfection, (or now-a-days UV Treatment). Please read what they have to say before you head into the ...


14

In the core alps (Liechtenstein, Switzerland, and Austria), you can drink water almost everywhere directly without filtering. There are only two exceptions: If there is a thing or something like this that forbids drinking it, or if you can see an obvious reason not to drink it, like for example a strange smell or abnormal color. In the other countries in ...


14

I'm going to chime in on a more practical answer. The question is not "What is the scientific case for Giardia". The question is "Why are people so scared of it?" "Or why is everyone so scared of it now, when no one seemed to care before?" Or in other words, we're not talking about how dangerous Giardia is, but rather why people are worried; specifically ...


14

A watertight container is what is required here. The best thing is metal but if we're without this you can use plastic bottles on the shoreline folded paper a hollowed out and charred piece of wood* bamboo* broad leaves shaped using twigs* birch bark* dig up some clay, create a bowl and throw it in the fire carve a wooden bowl use strips of wood, bound ...


13

As Cryptosporidium is passed in the faeces of animals, the more heavily the land is used by animals, the greater the risk of Cryptosporidium contamination in water sourced from that land. This article suggests some ways (quoted below) to avoid Giardia (which has a similar lifecycle to Cryptosporidium), conversely, if you are unable to source water following ...


12

Boiling kills everything -- giardia, cryptosporidium, other bacteria, and viruses. 185°F (85°C) for a few minutes will do it, and boiling for one minute will do it. (Boiling is lots of big bubbles, not just a few small bubbles on the side of the pot.) Some people recommend longer boiling times at higher altitudes because water boils at cooler temperatures ...


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