How To Tell If Water Is Safe To Drink In the Wild


Crystal clear water, running through a stream or river, does get cleaned a bit by natural processes flowing over rocks, vegetation, and other natural filters. But, if your drinking water is just downstream of any unknown water source, it could very well be contaminated by humans or animals and what may seem to be very clean and pristine may not be. How do you tell if water is safe to drink in the wild?

  • As a rule, don’t drink from any source of H2O in the wild without filtering or boiling but if you must:
  • Drink from fast water
  • Smell for signs of contamination-foul, chemical & Sulfur
  • Look for life insects birds & fish
  • Surface algae, slicks, oily films & foam
  • Cloudiness & turbidity
  • Carcasses
  • Poop on rocks

We can survive for weeks without food, but only for a day or two without a source of drinking water, depending on the activity, even less.

Not only does a lack of water lead to dehydration, but our water intake regulates body temperature, improves physical and cognitive performance, and prevents hypothermia and hyperthermia. When outdoors you need to make sure you have drinking water resources or can recognize the dangers of contamination.


Dangers of Drinking Stream Water


With so many items to buy for backpacking and hiking outside, there are plenty of ways to survive outdoors. Outside portable drinking water filters with Carbon filters combined with Miro-filtration media are commonly found that are smaller and lightweight.

They can make almost any water safe and can filter and source water from a river to streams. They are available for any situation from water filter bottles to desalinators for serious hikers in any environment.

Still, there are times when people can get into situations where they are separated from a filter that will clean water for many different reasons.

It happened to me and the people who were hiking became separated from our main source of water while climbing a small mountain by trail rated at class 2. 

The kids went with us in a group of 6-8 with some who were at different skill levels and in better shape. That was the problem. After a short while, we became separated and the hiker who carried the water was farther up the 5-6 mile trail.

Soon after that water became a problem and there were no other hikers to count on for myself and my daughter who started to show signs of dehydration.

With no one else in sight and no cell phone, (it was the early to mid-1990s) I had to make a decision on drinking spring water coming through the mountain walls as we climbed higher or risk dehydration.

My background was in water treatment and I knew the risk of drinking water from an unknown source but my daughter wasn’t looking right. She was sweating then stopped and was confused. It had gotten hotter as we climbed.

So I looked for spring that was coming through the walls of the trail and found what I thought was a good stream of water coming through the rock and soil. I took my teeshirt off and rinsed it a few times then saturated it with clear water. I squeezed it into her mouth and wrapped the shirt around her neck.

This revived her until we met up with the rest of the group up the trail and we both had plenty to drink.


I made the right decision (Thank God!) because the risk of dying from Severe Dehydration outweighs drinking contaminated water.

According to Dr. Troy Madsen from the Health Anniversary of Utah:  “If I were out somewhere and I needed water and I just felt like the thirst was going to affect my ability to get out of an area or hike out, I would drink the water.

We’re talking either about the immediate danger of severe dehydration versus the risk of an infection that’s not going to hit you for one to two weeks, and that can typically be treated with antibiotics. So if I had to weigh the risks, I would err on the side of that infection.

Dr. Troy Madsen: If you ever are out hiking or backpacking, the best to have is just carry some iodine tablets. I like to do some trail running, and just in the little handheld water bottle I carry.

I’ve got a little packet with a couple of iodine tablets because I figure if I’m out somewhere in the mountains and there’s a water source there, but I’m too far away to really refill my bottle and I need some water, that’s some option.

It’s easy to do. That’s going to take care of most things. So it’s very simple. You can also carry water filters, which are very simple


Is Fast-Moving Water Safe to Drink


Many people believe that fast-moving water is safer to drink than stagnant pools of water and in some cases it is. But chemicals, bacteria, and protozoa can exist in areas where the current is swift.

What’s upstream from that cool clean fast-moving flow of water can be a source of water that animals use as a toilet or a rotting corpse of a critter that decays in the pool just ahead.

Moving water carries more oxygen than a stagnant pool of standing water which can be healthier than a standing pond where there is none. In fact, it is an EPA classification for healthier water to carry good oxygen levels out in the environment. 

The problem is that the source of water upstream is a mystery and you should never drink from an unknown source in the wild unless there is no other solution. Even water going over a waterfall carries the risk of animals pooping in it upstream no matter how refreshing it looks.

Giardia and Cryptosporidium are two of the more common protozoan parasites that cause significant gastrointestinal illnesses that can be fatal. There are others as well. According to Dr. Maddsen Giardia is typically the big one.

That’s often what we think about with really kind of the classic case of someone who drank some stream water, comes to the ER, sees their doctor a week later just saying that they’re just having profuse, watery diarrhea. That’s usually the big risk.

There is no mechanical or chemical process at work that purifies the water moving through rapids or down a babbling brook, or over the long drop of a waterfall. No matter how nice it looks. Whatever contaminants are in the water remain even as it changes from a pool of standing water to white water rapids heading down to a waterfall won’t matter.

How to Tell if Water is Contaminated


  • Always look for signs of contaminants in the surrounding area. Dead animals rot and they leak bacteria into the water, which then spreads. Look for signs of animal carcasses, and remember that bacteria like cryptosporidium can be spread through animal fecal matter, so look for obvious signs of poop.
  • Small animals poop on rocks that water washes over into the stream that may be crystal clear but full of bacteria or parasites.
  • Another way to tell if water might be contaminated is to look for turbidity or cloudiness. Most water in the outdoors gets muddy after storms and then clears up but should be suspect if cloudy.
  • Use your senses is the water foul-smelling or has a chemical odor-chlorine scent-sulfur scent-metallic smells
  • Are their insects and birds living in the water’s habitat?
  • Surface algae or slick or oily film that may be oil from a leak or roadway or foam floating on the surface

How To Purify Water With Natural Materials


If you have a water filter, definitely then use it. If you use drinking water sterilization tablets, do so now. Filter it and then boil it, triple treat it. Whatever you do, do it. Just make sure you are treating it if you want to minimize the chances that you will contract something nasty from it.

A great portable filter is the Katadyn Pocket Water Filter, Long Lasting for Personal or Small Group Camping, Backpacking, or Emergency Preparedness available through Amazon. 

Generally speaking, things that make water undrinkable also make it misty or colored or foul-smelling and the things that are toxic that don’t affect the appearance of water are rare in open countryside, particularly in mountainous areas.

Is there an industry in the area like fracking or oil industries? There are ways to ensure that at the very least you make an attempt to purify water if you can. Some ways to do this:

  • Filtering the Drinking Water-Using natural material you can find outside including sand, plants, and charcoal
  • Boiling the water-Kills off Bacteria and Virus-The most familiar is boiling. Simply bringing water up to its boiling point of 212 degrees Fahrenheit will kill almost all microorganisms, so just a few minutes of boiling will do the job.
  • Making a Still -Evaporation and Condensation-


Under normal situations you probably won’t run into chemical contamination, you most likely will run into bacterial infection to deal with. Your safest bet is to distill through evaporation and capture condensation in another pot. Boiling, or using charcoal.

Carbon found in charcoal is a chemically active substance, with a tendency to bind to almost anything. At a microscopic level, charcoal is a heavily pitted and striated material, which vastly increases its real surface area. The result is that when water slowly runs over charcoal, pollutants find themselves glued to the charcoal surface.

The result is that when water slowly runs over charcoal, pollutants find themselves glued to the charcoal surface. An improvised filter can be made out of ground-up charcoal, a strainer, and a funnel. Bear Grylls made a purification drinking straw out of little more than a reed and some charcoal bits for the Discovery Channel’s “Man vs. Wild.”  It’s a simple technique, but it is highly effective.




How Does a Catholic Priest Make Holy Water

For more informative articles about all topics of H2O stay here on MyWaterEarth&Sky-Holy Water is always there in the church and available by a Catholic priest for ceremonies or special blessings, but not too many people even Catholics know where it comes.………. Continue reading




JimGalloway Author/Editor


References: Risk of Drinking Stream Water from the University of Utah

Methods of Water Filtration – from Sciencing 




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