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Why Boil Water In The First Place?

When you are in the backcountry and see pristine, pure water from a lake, pond, stream, or river, you might assume that the water is safe to drink. After all, the water is pure blue and clear, and you do not see any algae or other gunky crap floating.

So, what can go wrong?

To quickly answer your question, as it may contain nasty waterborne contaminants, drinking natural water sources can make you sick. And if you are immune-compromised, it can even kill you. Accordingly, boiled water is the most reliable and versatile method for killing germs, parasites, and bacteria in any water source.

Why Can’t Natural Water Sources Be Trusted?

Most urban dwellers and even some experienced campers assume that pure, natural stream water must be healthy. At first glance, this is not a reckless assumption. After all, stream water should be potable as it has not been treated with fluoride. More importantly, the water will not be contaminated with man-made pollutants. However, they very well may be wrong.

First of all, just because something is natural does not mean it is healthy. For example, opium poppies are natural. The opium dens of the 1800s, to be diplomatic, were though not very healthy. This same point is the same with natural water sources (I.E., Streams, Rivers, lakes). All can be contaminated with parasites, bacteria, viruses, and other contaminants.

Opium Den

Mostly Naural-Not Healthy Though 🙂

What To Look Out For In This Article

This article will go over the following:

  •  The two most common forms of pollutants that are found in wilderness water sources.   
  • Type of natural water sources that need purification. Limitations of other water purification methods.
  •  Various methods to boil water over a campfire.

And as a bonus, how to use plain bleach to purify water. 

The Two Most Common Natural Water Pollutants

Giardiasis and Cryptosporidiosis

 Giardiasis and Cryptosporidiosis, which are described below, are the two most common water pollutants that you may acquire in the wilderness.



Cryptosporidiosis Image from CDC

Giardiasis (AKA “Giardia”) is a parasitic microorganism that lives in your intestines. Once ingested, Giardia can be passed on by the way feces. What makes Giardia especially dangerous is that it can live outside the human body for months.

Symptom Onset

Giardia symptoms occur from one to two weeks after infection.


Microscopic Giardia parasites live in the intestines, which results in Gastro-Intestinal (AKA “G.I.”) distress. Some of the more notable symptoms are:

• Dysentery

• Gas

• Nausea or Stomach Aches

• Dehydration

• Abdominal Cramps and Pain


(AKA “Crypto”)


Crypto is a microscopic germ that also causes G.I. problems. Most people affected by Crypto only suffer diarrhea and other stomach-related issues. However, immune-compromised individuals affected with Crypto may be more severely affected. For example, immune-compromised individuals, like those with HIV or aids, can suffer life-threatening complications if they are infected.

Symptoms Onset

After infection, Crypto infection symptoms will start in two to ten days. Seven days though, is average. Crypto infection will last from one to two weeks, and the symptoms may also reoccur after you thought they have passed.

Typical Symptoms

Crypto is similar to Giardiasis in that it causes G.I. or stomach-related problems. A few common symptoms are listed below.

• Liquid Diarrhea

• Abdominal Pain and Cramps

• Dehydration

• Fever

• Weight Loss and Vomiting

What Types of Water Needs Purification?

I alluded to this earlier. But, this point needs to be emphasized.  NEVER ASSUME water is safe to drink when you are out camping in the backcountry. Water from a stream, lake, or river might look pristine. But, it still can be affected with Giardiasis, Cryptosporidiosis, or other types of natural or even man-made pollutants.

Water Purification Methods

Boiling Water

How To Boil Water Over A Campfire

The best surefire way to purify water is boiling. One obvious way is a portable stove, dutch oven, or other camping cookware. However, a camping stove needs fuel to operate, and as they are mechanical, they can and do break. Below though, are basic guidelines for using both a standard and the Ghillie kettle for boiling water.

Boiling Times May Vary-For altitudes of less than 5,000 above sea level, vigorously boiling water for at least a minute kills disease-causing bacteria and other harmful microorganisms. For 5,000 feet below sea level, boil for around five to seven minutes. Please note, these times are minimum. As a general rule, the longer you can boil, the better.


Cast Iron Dutch Oven Pre-seasoned Pot with Lid Lifter Handle, 5 Quart Camp Cookware Pot with Silicone Handles for Camping Cooking, BBQ, Basting, or Baking, Black Cast Iron

It is harder to boil water with a pot or a kettle. However, as a standard cast iron pot or kettles cannot break and do not need fuel for operation, they are a reliable container for boiling water.

To boil water over a campfire, you just heat up the water in the kettle to a rolling boil. As for the time needed for boiling, I have seen various figures. A few websites say that only one to three minutes of boiling is needed to kill water contaminants. Other sites state that, for optimum safety, water should be boiled from between five to 10 minutes. Personally, I would err on the side of caution and boil the water for at least five minutes.

Ghillie Kettle

The Ghillie Kettle was first designed in the 1900s in England and has many names: the Storm Kettle, Kelly Kettle, Volcano, and Thermette. It uses natural fuel sources, like twigs, dry leaves, and other tinder sources for operation. So, it works pretty well as a camping kettle. What’s most impressive about the Ghillie Kettle is that if you use this device, it only takes 1.5 or so minutes to get water boiling. The biggest drawback of the Ghillie Kettle is the price, as they are costly.


Boiled water will likely taste relatively flat. You can fix this by aerating the water by pouring it several times from one container to another.

Other Water Purification Methods

I’m not going to lie. When you are thirsty, boiling water is a pain in the A$#! So, instead of boiling, you may instead take a shortcut and use a Lifestraw (Or equivalent water filter) or Chlorine Dioxide water purifying tablets.

Lifestraw Water Filter

LifeStraw Personal Water Filter for Hiking, Camping, Travel, and Emergency Preparedness, 2 Pack, Blue

The life straw is a personal water filter that, by sucking through it, swiftly and effectively filters out nearly all water impurities. The life straw is an excellent solution for taking a quick sip of stream, river, or other forms of water found in the wilderness. (Assuming it is in good working order) ‘

A life straw’s primary limitation is that it can only be used for drinking water directly out of the source, not campfire cooking, washing dishes, etc.

Water Purification Pills

Potable Aqua Chlorine Dioxide Water Purification Tablets - 30 Count

When you have time to wait, water purification tablets can be an excellent water purification method. The two most common water purification pills are Iodine and Chlorine Dioxide tablets. 

Chlorine Dioxide Tablets

Per, if the directions are followed, Chlorine Dioxide tablets CAN effectively kill most waterborne contaminants. Notice, the CDC says, that Chlorine Dioxide CAN and not that it “WILL KILL” contaminates. 

Can You Wait Four Hours?

One of the biggest Chlorine Dioxide makers in the industry is Portable Aqua Tablets. Potable Aqua’s package, shown above, states that you need to wait four hours for the full effects of their pills to complete work. So, if you are not able to or do not want to wait for hours, you should consider boiling water instead. 

Stay Away From Iodine Tablet-Some aqua pills touted as water purifiers do not work for specific contaminants. As an example, Iodine does not kill cryptosporidium contaminated water. Also, Iodine water purification tablets can make murky, cloudy water taste even worse.

Bleach-Small quantities of bleach also purify. And bleach arguably is the best method for purifying multiple gallons of water. However, since this article deals with making backwater, natural sources of water potable, beach water purification will be addressed in the appendix at the end of this article.

Final Thoughts

The number one lesson that you should learn from this article is that wilderness water sources do not equal safety. When in the backcountry, assume that all water is contaminated and then purify the water accordingly. This means that you need to boil all water that you are going to use for cooking. Also, I would bring a Lifestraw with you for when you want to get a quick sip of water.


Bleach Water Purification 

Ordinary household bleach (like Clorox) can be used if you do not have water purifying tablets. Below are the instructions for using bleach water purification for individuals/small groups or multiple individuals.

Type of Bleach

Use standard, non-scented bleach. Ensure the bleach is fresh, as it only has a shelf life of around three months.

 Bleach to Water Ration

  • 2 drops= 1 quart
  • 8 drops= 1 gallon
  • 1/2 teaspoon= 5 gallons

 If the water is cloudy or filthy, double these recommended amounts.

How To Apply Bleach 

Individuals and Small Groups


  1. Filter-If needed, filter out any particles present in the water with cloth, coffee filters, or paper towels. 
  2. Pour In Bleach-The bleach to water ratio for sanitizing requires eight to 16 drops of bleach per gallon of water. Eight drops of bleach are sufficient for mostly clean water, and for murky or cloudy water, 16 drops will work.

Thoroughly mix the water, cover it for at least a half-hour. If the water has a slight chlorine smell, then the water should be safe to drink. If the water doesn’t smell like chlorine, you’ll need to double the initial drops and then wait for an additional 15 minutes to test the water again.

Large Quantities Of Water

Follow the below steps:

  1. Wait for the particles to settle before doing anything.
  2. If applicable, filter out any particles in the water with cloth, paper towels, or even coffee filters.
  3. Pour the filtered water into a sanitized container. Then, add one gallon of Clorox, type bleach for every 3,800 gallons of water.
  4. Mix the water thoroughly and then wait for thirty minutes
  5. You’ll want the water to have a faint bleach smell. If it does not add more bleach, wait for another 15 minutes and then test for the bleach smell.
  6. Water should be safe to go when you smell the bleach.

Best Practices

As part of disaster prep, you should keep an eyedropper taped to the bleach bottle.

How Do You Know If The Water Is Safe To Drink?

If there is too strong of a chlorine taste, air the water out by repeatedly pouring water from one container until the water tastes better. Also, a small pinch of salt for each quart of water boiled helps improve the water taste.

Water Sanitation

If the SHTF, proper sanitation is essential. This means that you need to have methods to properly clean your pots, pans, dishes, and other kitchen utensils. However, it is next to impossible to clean your kitchen utensils by way of steaming hot water. So, you’ll need to use bleach for sanitizing the kitchen.

For kitchen sanitation, all you need is to mix one tablespoon of bleach for every water gallon. You then wash, rinse, and soak the dishes in the bleach/water mixture for at least two minutes.