How To Purify Water in the Great Outdoors:  5 Ways to Make Lake or River Water Safe


Regardless whether you are hiking, kayak fishing or hunting, any outdoor trip can go quickly awry in a hurry if you aren’t geared with the proper survival equipment or don’t have a clean water supply.

If you’re not carrying your own water in with you, you’ll need to purify the water you find in the wilderness.  To purify water while camping, you have five great options:

Let’s look at 5 great ways to purify lake or river water next time you’re out in the sticks.



Boiling water is a simple and effective way to purify water for drinking. There’s nothing to it: Collect the water into a pot or other container, put it on the camp stove, and bring it to a roiling boil and boil for at least one minute.

At altitudes above 6,562 feet, boil the water for at least 3 minutes, since because the air pressure is so low there, water takes less energy to hit the boiling point. This means that the water will boil at a lower temperature than usual but the boiling time will need to be increased to purify water or cook meals.

Boiling kills the bacteria, viruses, and protozoa that may ruin your trip. However, boiling does not remove the mud and other particulate matter found in backcountry water.

But if you’re patient, you can leave the water out for a bit and the mud will settle to make drinking more pleasant.

The Good:

  • Boiling water is relatively safe, cheap, and effective
  • It does not require expensive gear and special expertise
  • Boiling water is the go-to method of many outdoor enthusiasts

The Bad:

  • Some nasties in water might not be nixed at the boiling point; you’ll need a pressure cooker to kill those bugs, but fortunately they are very rare;
  • Boiling does not remove the dirt, heavy metals, and pollutants from water.

If you aren’t used to boiling your own water in the Great outdoors, below is a quick video with a demonstration as well as the pros and cons.

Chemical Treatments:  

The most common commercial water treatments come in two basic types: chlorine and iodine. Chlorine is available in tablets that you dissolve in water and let sit for 15 minutes.

Chlorine can be also replaced by liquid household bleach, just make sure that it hasn’t expired and doesn’t have any added fragrances in it. Use half of teaspoon of bleach to 5 gallons of water. Double the dose, if the water is really murky.

Wait 30 minutes before drinking the water. If the water doesn’t have a bleachy smell add just as much bleach and wait 15 more minutes.

Make sure that no more than 6 months have passed between the bleach’s manufacturing date and the use date for maximum effect. After around 6 months bleach starts to lose its potency.

Iodine, which can be purchased as tablets, crystals, or tinctures, works the same way, though iodine should not be used by pregnant women or people with thyroid issues.

For both methods, it is best to pre-filter the water to remove dirt and particles free floating in the water. You can use a clean T-shirt or a bandanna.

The Good:

  • Quick and convenient (no need for a stove and fuel)
  • Save on fuel bigly
  • The go-to method of many ultra-light backpackers

The Bad:

  • Chemical water treatments should not be used extensively as they have a cumulative effect, slowly overloading your body with chemicals
  • Chemical treatments often fail to kill giardia as the tiny bug is almost immune to the chemicals
  • Heavy metal contamination, debris, and pollution are still an issue
  • Water does not taste (or smell) that great after chemical purification

If you aren’t familiar with the chemical treatment of water, below there’s a short tutorial.

Gravity-fed Water Filters:  

Water filters are great options for purifying water when camping. They’re easy to use, and are available in personal or larger, portable models for two or more people.

Filters do a good job on protozoa and bacteria, but will not filter out viruses. Water filters work by straining the water through an internal element using a hand pump, gravity, or in a sip tube. They also leave the mud out, so you get a nice clean drink.

The Good:

  • Cheap
  • Can filter out large quantities of water
  • You can make your own filter

The Bad:

  • They take a lot of time to work
  • Just for camping
  • Not 100% effective

Below there’s is a quick method to make an emergency water filter by yourself.

Portable Water Purifiers:  

Water purifiers are the next step up when it comes to convenient solutions. Most water purifiers are a combo of a filter and chemical compounds or, most recently, a multiple filter system.

To be marketed as a water purifier in the United States, the device must meet or exceed the U.S. Environmental Protection Agency’s (EPA) Guide Standard and Protocol for Testing Microbiological Water Purifiers.

EPA-registered products must kill 99.9999% of bacteria, 99.99% or viruses and 99.9% of protozoa. Water purifiers are currently very affordable and provide safe, reliable filtration.

The Good:

  • They kill pathogens down to 0.2 micron in size
  • Very portable and lightweight
  • You can filter water as you go

The Bad:

  • Portable water filters do not kill viruses because of the small size (they need to be backed by other water purification methods)
  • You’ll need to put some serious elbow grease into getting enough water to drink

Below, there’s a quick review of three very popular water filters.

The Ultraviolet Light Method:  

Ultraviolet light can also be used to purify water. At the correct intensity, UV light contains ample radiation to destroy the DNA in microbes and shut down their reproductive mechanisms, making water safe to drink.

Most UV purifiers pass water through a UV irradiated chamber to sterilize it. The downside to UV purification is the price: Even a simple handheld unit is very costly.

However, UV radiation uses absolutely no chemicals, leaving you with pure, tasty drinking water.

One key to making the UV filter work properly: The water should be pre-filtered to remove sediment before purifying as to not obstruct the UV light.

The Good:

  • Quick, easy, convenient
  • No nasty chemicals are added to the water
  • Water tastes and smells fresh
  • You can filter as much water as you want (you’ll not run out of fuel or tablets)

The Bad:

  • Water will become unsafe to drink if exposed to visible light after the treatment
  • Pre-filtering is a must for the best results
  • UV-based water treatment devices are a bit pricey

One popular UV water sterilization  device is the Steri-pen. You can see the product broken down in the video below.

Wrap Up:

While there are several ways to make sure the water you are about to drink is clean, any of the methods mentioned above should keep you out of harms way on your next outdoor excursion.


We are not responsible for any unsuccessful attempts by you to purify water.  The suggestions above are meant to be used by users to purify their own water but at their own risk.

The Out sider

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