Is Untreated Water Safe To Drink? (Pathogens & Safety)

Water! There is nothing more important to our survival. While nearly 71% of the world is covered in water, only 3.0% is freshwater. And of that, only 0.5% is easily accessible because the rest is trapped in glaciers, polar ice caps, permafrost or buried deep in the ground. Most of our drinking water comes from rivers and streams. 

Given the significance of sustaining our very existence, it’s no surprise that access to clean drinking water is a fundamental human right and critical in any situation.

In a perfect world, water would be crystal clear, invigorating and free of pathogens such as bacteria, parasitic protozoans and viruses that cause waterborne illnesses globally.

Pathogens cause life-threatening waterborne diseases such as cholera, typhoid, and diarrhea which significantly impact human health.

Waterborne disease-related deaths are more common than anyone can imagine. The World Health Organization estimates that 3.4 million people die a year. It kills more people than warfare, terrorism and all other forms of violence combined.

If you believe this only applies to underdeveloped countries, kindly reconsider your position. The CDC estimates that 7.2 million Americans are sickened annually from diseases proliferating in water sources.

Unlike animals that gulp up water wherever it's found, we just don’t have that luxury - at least not without the probability of acquiring serious illness and possible death.

Equipment that filters or purifies water is one of the most important pieces of gear you can carry. Why? Look at the alternative. Quenching your thirst without proper filtration or purification is an open invitation for pathogens.

Just a sip can make you sick. Be prepared and avoid the pain later!

In this Guide, you will learn:

  • What are pathogens?
  • What types of pathogens cause waterborne illnesses?
  • What happens when a bacterial pathogen is ingested?
  • And much more!

Now that I have your attention, let’s continue. 

What Are Pathogens?

Have you ever thought about who lives in the river? What immediately comes to mind are beavers, fish and turtles. However, I can guarantee you never thought about the pathogens that call it home. These unseen invaders are just waiting for you to guzzle them up.

Waterborne pathogens are microscopic organisms that can be broken down into three primary groups: bacteria, protozoan parasites and viruses. Like any other organism, they simply try to live and procreate. However, they live at your expense because you are the host and these unwelcome guests call you breakfast, lunch and dinner.

Your body is a desired ecosystem for pathogens because it is moist, nutrient rich, warm and for the most part remains at a constant temperature. No wonder these pathogens welcome unsuspecting thirst-driven individuals to gulp them up.

They are the most common and widespread health risk associated with drinking or coming into contact with water contaminated with animal or human feces. Consumption initiates infection of the gastrointestinal tract.

These pathogenic nightmares cause waterborne illnesses such as Cholera, Cryptosporidiosis, Diarrhea, E. coli, Giardiasis, Salmonellosis and Typhoid, to name a few. Infections can range from asymptomatic to life-threatening, depending on the species and the host. 

The World Health Organization estimates that diarrhea, an illness caused by waterborne pathogens, kills 525,000 children under the age of 5 a year. 

Now that you are aware of these diabolical pathogens, let’s take a look at several types of illnesses they cause.

What Types of Pathogens Cause Waterborne Illnesses? 

All pathogens have one thing in common. In order to cause a waterborne illness, they need to invade a host. Any drop of untreated water from a lake or river can invite marauding pathogens to initiate a waterborne illness. That’s not even a sip!


Although bacteria are primarily harmless and beneficial, some are pathogenic and cause waterborne illnesses. A few common culprits are as follows:

Escherichia Coli - commonly referred to as E.coli. Symptoms include severe stomach cramps, diarrhea, vomiting and fever.

Shigella- causes Shigellosis, whose symptoms include diarrhea (sometimes bloody), stomach pain, fever, and the feeling to defecate even when the bowels are empty.

Vibrio Cholerae - causes Cholera, whose symptoms include profuse watery diarrhea sometimes described as “rice water”, vomiting, thirst, leg cramps, relentlessness and irritability. If left untreated, severe dehydration can lead to shock, coma and death within hours. 

What Happens When Bacterial Pathogens Are Ingested?

Bacterial pathogens transmitted by contaminated water infect the gastrointestinal tract and are excreted in the feces of infected humans and animals.

For example, Salmonella can be found in food and water sources contaminated with feces of infected humans or animals.

When ingested, the bacteria passes through the stomach and colonizes the large and small intestine. There, they invade the intestinal mucosa and multiply. The bacteria spreads into lymphoid tissues of the gastrointestinal tract and eventually into the bloodstream infecting organs such as the brain, liver and bones. Infection caused by this bacterium is called Salmonellosis. 

Burkholderia pseudomallei, which causes Melioidosis, is found in contaminated water and soil. This disease is widespread in Southeast Asia and Northern Australia. It was evaluated by the United States and the former U.S.S.R. as a potential biological weapon.


Pathogenic protozoa are one-celled microscopic parasites that are able to multiply in animals for humans once ingested. Infections can range from asymptomatic to life-threatening, depending on the species and the host.

They can be found in ponds, rivers, streams, swamps and soil. These monsters are transmitted by drinking water contaminated by the fecal matter of an infected animal or human.

Two of the most common protozoan parasites causing waterborne illnesses are as follows:

Cryptosporidium - is a microscopic parasite that is found in food, soil and water that has been contaminated with the feces from an infected animal or human. It causes Cryptosporidiosis whose symptoms are watery diarrhea, stomach cramps or pain, nausea, vomiting, fever, weight loss and dehydration.

Giardia - is a microscopic parasite that is found in food, soil and water that has been contaminated with the feces from an infected animal or human. This microbe causes Giardiasis whose symptoms are upset stomach or nausea, stomach or abdominal cramps, gas or flatulence, diarrhea, greasy stool that floats and dehydration.

It is estimated that Giardia infects 1.2 million people in the United States a year according to the CDC

Giardiasis also known as "Beaver Fever" gained publicity due to an outbreak that occurred when hikers drank stream water contaminated with Giardia from beavers at Banff National Park. 

What Happens When Parasitic Protozoans Are Ingested?

A parasitic protozoan in its dormant stage is called a cyst. The cyst wall functions to protect the organism from deteriorating in the environment. As the parasite undergoes a dormant period, it patiently waits to be ingested by a host. It can survive days or even weeks in the environment.

When the cyst is ingested, it erupts into its active stage, (called a trophozoite). For example, Giardia, in its active stage, attaches itself to the small intestines with a “sucker”. It starts to feed by taking up nutrients and quickly replicates causing the signs and symptoms of Giardiasis.

Some of the trophozoites will develop into cysts instead of undergoing replication. When the sicken host defecates, these cysts contaminate the soil and waterways. Giardiasis is immediately infectious once passed through feces. 


There are over 100 types of pathogenic viruses excreted in animal and human wastes that contaminate water. Waterborne viruses threaten both animal and human health and cause an alarming array of diseases and symptoms.

It is well-known that bacteria and parasitic protozoans transmitted waterborne illnesses in contaminated waterways. What is less appreciated are viruses in these same waterways that significantly impact human health.

A few examples of viruses that cause waterborne illnesses are as follows:

Rotavirus - are found in the United States and throughout the world. It may be found in water sources such as private wells that have been contaminated with feces from infected humans. Symptoms include vomiting, diarrhea, loss of appetite and dehydration. It is especially dangerous for infants and young children.

Norovirus - is found in the stool or vomit of an infected person. It is transmitted by swimming or drinking water contaminated by infected persons. Symptoms include headache, fever, abdominal cramps, diarrhea, nausea and vomiting. This virus is very contagious and can spread rapidly.

Hepatitis E (HEV) - causes liver disease and is transmitted by drinking from water sources contaminated with the feces of infected humans. Symptoms appear 15-60 days after exposure and consist of the following: fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, jaundice, dark-colored urine, grey stool and joint pain.

HEV is not commonly acquired in the United States, and most cases have been linked to individuals who have traveled to countries where HEV is endemic. 

What Happens When a Viral Pathogen is Ingested?

Unlike bacteria and parasitic protozoans that rely on each other to replicate in your intestines, viruses invade living cells in your body. It’s a brutal and complete takeover.

A virus attaches itself to a healthy cell (called the host cell), enters it and releases its DNA or RNA. This is the genetic material required to make copies of the invading virus.

Once inside, it completely takes over the healthy cell and coerces it to replicate the virus. The infected host cell dies because the virus suppresses it from performing its normal functions. When it dies, it releases new viruses which infect other cells.

Now that you understand waterborne pathogens are a serious threat, it’s important to realize how these disgusting microbes invade our waterways. 

How Do Pathogens Enter Waterways?

Conclusively, the source for waterborne pathogens is almost always from fecal matter of infected humans or animals whether they are asymptomatic or infected.

Surface water is always exposed to the environment and it will always be in contact with animals and humans (and their excrement) and is highly susceptible to pathogenic contamination. Mother nature does not have the luxury of pulling a tarp over her natural resource to protect it.

Keep in mind that large bodies of water such as rivers are supplied by other sources such as creeks, streams, and precipitation runoff. Ever wonder what’s going on upstream? Think before you drink! 

In 1993, the largest outbreak of a waterborne illness in U.S. history occurred in Milwaukee, Wisconsin. Over 403,000 people contracted Cryptosporidiosis and 69 died. This was the result of a failure in the treatment of surface water serving the population. 

Fecal matter can come into contact with water in so many ways such as:

  • Direct animal and human excretion.
  • Wildlife contact with surface water.
  • Raw sewage / combined sewage overflow.
  • Faulty septic systems.
  • Sewer line leakage.
  • Improperly managed livestock facilities / agricultural runoff.
  • Fields where manure or sewage is applied as fertilizer.
  • Camping areas with primitive toilets.
  • Pet waste especially in areas where this may be concentrated such as kennels.
  • Groundwater located within close proximity to contaminated surface water.
  • Urban runoff.
  • Aerosols emitted from sewage treatment plants.
  • Vessel wastewater discharge.
  • Insufficiently treated water.
  • Private wells that receive treated or untreated wastewater directly or indirectly.
  • Natural disasters such as drought, earthquakes, floods, hurricanes, winter storms and tsunamis. 

The above-mentioned is not exhaustive by any means. However, if you never thought about how fecal matter comes into contact with our waterways, I’m sure you’re disgusted by now. 

What does this mean to all of us? It simply means that we are all susceptible to waterborne pathogens.

How To Protect Yourself And Others From Pathogens.

Think before you drink! Drinking untreated water in the wilderness is risky and increases your chance of contracting one or several of the above-mentioned pathogens. Nobody wants to be hunched over in pain, vomiting and suffering from diarrhea. 

Here are a few pointers on how to prevent waterborne illnesses. 

  1. Common sense - Never drink untreated water from lakes, springs, streams, rivers, ponds, shallow wells or ground water at risk of containing pathogens. Most likely, it is contaminated with animal feces. 
  2. Don’t drink from water sources with high traffic - (i.e animal footprints, broken branches, or other obvious signs of disturbance). Your likelihood of encountering pathogens increases in high traffic areas near watering holes. Stay vigilant and look for signs of heavy usage. 
  3. Avoid water near pastures where animals graze - chances are it is contaminated with animal feces. 
  4. Boil Water - before drinking it from an unknown source. It is the surest method to eliminate pathogens. The Center for Disease Control (CDC) recommends you bring water to a rolling boil for one minute. However, at elevation above 6,500 feet, boil it for three minutes. 
  5. Be prepared - having the right equipment to filter and purify water gives you a piece of mind. 
  6. Keep It Clean - when camping, hiking or hunting through the wilderness, don’t relieve yourself in a water source. 
  7. Observe good outdoor habits to help protect others - bury human waste eight to ten inches deep and at least 100 feet from water sources. 
  8. Avoid Water Sediment - pathogens also lurk in soil. 
  9. Avoid food or drinks - prepared with untreated water. 
  10. Alcohol-based sanitizers - if treated water is unavailable, use them to disinfect your hands. 
  11. Wash your hands - before eating and handling food. 
  12. Never handle wild animal fecal matter - we all know this, but children on the other hand are unable to appreciate the danger of pathogenic exposure. Please be mindful of your younger companions. 
  13. Don’t enter unknown water with an open wound “if possible”- pathogens can enter an open wound and cause infection. 
  14. If you must drink untreated water - flowing water is your best option because the movement doesn’t allow pathogens to fester. Remember, stagnant water always increases your chance of gulping down unwanted guests. 
  15. Know your environment - even under the most ideal conditions, nature is quite formidable. Don’t immediately assume that crystal clear water is safe to drink. A simple mistake can lead to a world of agony. 

A few tips can make all the difference. Remember, you could be asking for trouble if you don’t treat the water before ingesting it. 

What Types of Portable Equipment Removes Pathogens From Contaminated Water?

Due to the high risk associated with drinking water contaminated with pathogens, the demand for outdoor water filtration and purification equipment has never been higher. Ingesting pathogens definitely leads to undesirable consequences. Why risk it, when you don’t have to.

Many types of portable water filters and purifiers are available. Simply adding one to your kit gives you a “piece of mind” that you will not fall prey to these microscopic hordes. 

Portable Personal Straw Filters


Sawyer Mini Water Filtration System

  • Ideal for outdoor recreation and emergency preparedness.
  • Removes 99.999%of bacteria, parasites, microplastic, chlorine and organic chemical matter.
  • High performance 0.1 micron absolute inline filter.
  • Fits in the palm of your hand and weighs just two ounces.
  • Superior filtration and maximum versatility.
  • For over 10 years, Sawyer has had a life-saving impact in the lives of those without clean drinking water. 

The Sawyer Mini Water Filtration System is an excellent outdoor companion. It is equipped with a 0.1 micron absolute filtration removing 99.999% of all bacteria, such as salmonella, cholera and E.coli, and 99.9999% of all protozoa.


LifeStraw Personal Water Filter

  • Award winning water filter.
  • Ideal for outdoor recreation and emergency preparedness.
  • Transforms 1000 gallons of contaminated water into clean and safe drinking water.
  • Removes bacteria, parasites and microplastics.
  • All filters are rigorously tested.
  • For every LifeStraw purchased, a child in need receives safe water for an entire school year. 

The LifeStraw Personal Water Filter is sturdy, durable, light and compact.  At only 2 ounces, it can be easily stowed away in your kit or pocket. Equipped with a 0.2 micron filter, it removes 99.999 percent of bacteria, parasites and microplastic from water. 

Gravity Water Filters


Sawyer 1-Gallon Gravity Water Filter

  • Ideal for outdoor and emergency preparedness.
  • Weighs only 2 ounces.
  • Filters large quantities of water in 7 minutes.
  • Wide mouth cap allows for fast filling.
  • Rated to filter up to 100,000 gallons of water into clean safe drinking water.
  • 0.1 absolute micron filtration.

Just sit back and let gravity work its magic. This amazing 0.1 micron filter from Sawyer removes 99.9999% of all bacteria, protozoa, cysts and 100% of microplastics. Just hang the unit on a nearby tree or tent pole and go about your day while the filter processes your water.

The set is well-equipped with a Sawyer Mini water filter, a durable one-gallon bladder, cleaning plunger, cleaning coupling and gravity hose. 


Platypus GravityWorks High Capacity

  • Ideal for outdoor and emergency preparedness.
  • Filters up to 1.75 liters a minute without pumping.
  • Light and compact, it weighs 11.5 ounces.
  • Field cleanable, microfilter can be easily backflushed in 4 seconds to maintain filter performance.
  • Designed to easily collect water.
  • Constructed from high-quality materials.

No pumping required. Fill, hang and relax. This robust filter is also intended for larger outdoor groups or basecamps. It removes 99.9999% of all bacteria, protozoa, cysts and 100% of microplastics.

Just hang it up, walk away and come back to clean filtered water to quench your thirst. It comes with a clean reservoir (4.0 or 6.0L), dirty reservoir (4.0L or 6.0L), hollow microfilter, hoses, shutoff clamp and storage sack. 

Squeeze Filters


Sawyer Squeeze Water Filter

  • Ensures you have access to clean water anywhere in the backcountry or anywhere in the world.
  • Weighs 3 ounces and fits in the palm of your hand.
  • 32 ounces collapsible reusable squeeze pouches roll up when empty and easy to store in your kit.
  • Reusable 0.1 micron filters up to 100,000 gallons.
  • Included adapter kit makes this squeeze filter highly-versatile.
  • Screws onto water or soda bottles with a standard threaded top.

Don’t let this filter’s compact size fool you. Inside is a powerhouse of ultimate protection. The 0.1 micron filter removes 99.99999% of all bacteria, protozoa and 100% of microplastics. Its versatility is ideal for the active hiker, hunter, explorer and world traveler.

Lightweight and easily stored away in your kit or suitcase it comes equipped with two reusable 32-oz BPA-free collapsible pouches, drinking straw, one set of Sawyer Inline Hydration Pack Adapter for filter, and a mesh storage bag. 


Survivor Filter Squeeze Water Filter

  • Used for hikes, emergency preparedness and international travel.
  • Lightweight and easy to store.
  • Equipped with a three stage filtering process.
  • Super-fast flow rate of 13.5 ounces a minute.
  • Can attach to a standard threaded water bottle.
  • Filters are removable and can be cleaned or replaced. 

You’ll spend less time worrying about finding safe water with this impressive companion. This one-of-a-kind squeeze filter uses a triple filtration consisting of mesh cotton pre-filter, ultra membrane filter and carbon filter.

This filtration system removes 99.999% of bacteria, protozoans and viruses. It also removes 99.5% of mercury and 93% of lead. How’s that for protection!

Water Purification Tablets

You can also pack water purification tablets in your kit. Be careful because you’ll need to pay close attention to the expiration date. Keep them stored properly and follow package expiration guidelines.

A water purification tablet must have the ability to kill all microorganisms including viruses. They may not taste great but functionality over flavor is of the utmost importance in any survival situation.


Katadyn Micropur MP1

  • Effective against viruses, bacteria and parasites such as Giardia and Cryptosporidium in all water conditions.
  • EPA-registered as a microbiological water purifier.
  • Each tablet is measured to treat 1 liter of water.
  • No unpleasant taste.
  • Katadyn products are used by militaries and health organizations worldwide.
  • Katadyn is a global leader in
    portable water treatment. 

Simple, inexpensive and highly-effective, Katadyn Micropur MP1 tablets are used by militaries and health organizations world-wide

It is effective against bacteria, parasites and viruses in all water conditions. This product is EPA-registered as a microbiological water purifier. Katadyn is a global leader in portable water treatment. 


Potable Aqua Chlorine Dioxide

  • Used by campers, hikers, militaries and emergency organizations.
  • Effective against E. Coli, Cholera, Salmonella, Giardia and Cryptosporidium.
  • Improves taste and odor of water.
  • Ideal for use with hydration packs.
  • Meets EPA microbiological purifier standards.
  • Has 2.6 times the oxidizing capacity of chlorine. 

The inexpensive water purifying tablets are effective against bacteria, cysts, protozoans and viruses as a chlorine dioxide water treatment. They make sketchy water suitable to drink.

These mini companions have 2.6 times the oxidizing power of chlorine. These tablets are used by outdoorsmen and women, militaries, emergency organizations and anyone who needs to drink water of sketchy quality.

You don’t want to risk consuming contaminated water loaded with pathogens. They eagerly await your thirst and that first sip. If that ever happens, it will become your worst nightmare unless you are prepared for it. 

Final Note.

There is nothing more important to our survival than uncontaminated drinking water. Given its significance in sustaining life, it’s no eye-opener that access to clean water is a basic fundamental human right.

However, we do not live in a perfect world and pathogens plague humanity with debilitating and life-threatening waterborne illnesses. They claim the lives of 3.4 million people a year, more than warfare and other forms of violence combined. This is not a phenomena that solely occurs in underdeveloped countries. As a developed and industrialized society, we can never underestimate microscopic threats.

Know your enemy. Bacteria, parasitic protozoans and viruses patiently lurk in all waterways just waiting to be consumed. They spread E.coli, Giardiasis and Rotavirus. Their developmental stages are sickening and they are happy to call you their meal.

The primary source for waterborne pathogens is fecal matter of infected humans or animals whether they are asymptomatic or infected. Pathogens can naturally contaminate water from direct animal and human excretion, faulty sewage systems, improperly managed livestock facilities and mother nature’s violent storms. We never know what’s going on upstream. Never assume the water you are about to consume is safe.

Simple tips from boiling water to avoiding stagnant water pools can save you from a world of anguish and pain. Always have your guard up.

You don’t have to accept the risk of drinking water infested with squirming pathogens. A hunter doesn’t walk off into the woods without ammunition right? So, why not equip yourself with a water filter or purifier. It just makes sense. Many types of portable water filters and purifiers are available. Simply adding one to your kit gives you a “piece of mind” that you will not fall prey to these microscopic hordes.

However, there is always an exception. If death from dehydration comes knocking at your door, and you cannot treat the water, by all means drink it anyway. It’s better to acquire an unwanted pathogen than lie motionless and pathogen-free.

We welcome all comments. 

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