The Complete Guide on How to Purify Water in the Wild

When it comes to surviving in the wilderness, what’s the most important thing you think you’ll need? It won’t be as comfortable, but you can certainly make it without a tent, especially during the warmer months. If you don’t mind being a little hangry and weak, you can also survive for a couple of weeks without food. But water? Well, that’s a little tougher to go without.

Knowing how to purify water in the wild is a skill that all trekkers should have in their back pocket. Oftentimes it isn’t possible to pack enough bottled water to last your entire journey, and that’s especially true when it’s hot outside and you need to drink more anyway. So let’s take a look at some of the best ways to purify water on the trail.

Key Takeaways:

  • Lakes, rivers, streams, snow melt, and gypsy wells are potential water sources.
  • Boiling water is effective against bacteria but it won’t remove chemicals.
  • Convenient and effective, tablets contain iodine, chlorine, and chlorine dioxide to purify water.
  • Filtration bottles are efficient at removing pathogens, metals, and chemicals.
  • Distillation converts saltwater to freshwater, which is useful when freshwater is scarce.
  • Solar Water Disinfection uses sunlight to kill microorganisms.
  • Utilizes pores to filter dirt, microorganisms, and bacteria, ceramic filters are a good option.
  • Create a sand filter using a plastic bottle, pebbles, gravel, and sand.

Why Purify?

Having enough water is one of the 10 essentials for surviving in the wild. But in spite of the abundance of natural water sources, it should be obvious that drinking without purifying the water first is a bad idea no matter where you are in the world. It doesn’t matter how clear it looks, whether it’s glacially fed, fresh from a spring, or straight from a lake, it’s important to value your health and purify all water before you drink it.

The most common dangers are the bacteria and other pathogens that live in these places. E. Coli, Giardia, Cryptosporidium, Legionella, and many others have brought disease and death to countless people over the ages. Many of these bacteria slip into the water source from animals that don’t know it’s a bad idea to go to the bathroom in the same place you plan to drink from. It’s these gut bacteria that live in fecal matter that tend to be the most sinister. To avoid ingesting such dangerous organisms, it’s important to know how to purify water in the wild.

Finding a Water Source

three men getting water from a river

Before you can filter water, you need to find an adequate source. Your options will vary depending on where you are in the world, but in general, you’ll be able to discover water in one of these places:

  • Lakes, rivers, and streams. These are likely going to be the most prevalent options wherever you go. You’re more than welcome to drink from any of these sources, but be aware that you run a greater risk with lakes and rivers, in particular. Lakes are stagnant and home to a wide variety of microorganisms, and rivers are well known for funneling dirt and bacteria – especially if there’s an animal pasture somewhere upstream! Depending on the quality of the water, you may need to pre-filter it to remove any solid matter.
  • Snow melt. This one is more relevant for those of you camping in the mountains or during winter. Target snow that’s white (not black, brown, yellow, or some other questionable color) and plop it in a container that already has a little water sitting in the bottom of it. Put it on a low amount of heat, so it melts quickly without getting too warm. Hot or boiled snow water tastes awful! Generally speaking, if you grabbed pristine, white snow, you shouldn’t even need to filter it. However, best practice would be to run it through a filter of sorts after it’s melted.
  • Gypsy well. Random, stagnant bogs of brown water can be found almost everywhere. Obviously, you don’t want to drink this smelly goop! But mixed in with all the mud is a fair bit of water that would be a shame to waste, especially if it’s difficult to find another source.

    Next time you find a spot like this, try digging a hole a foot away from it. Water from the bog will filter through the dirt before trickling into your hole – once it’s filled up, you’ve got yourself a gypsy well. You’ll still need to purify it, but at least now you have a water source that won’t make you gag when you look at it!

Methods of Purification

1. Boiling

kettles sitting on a bed of coals

One of the cheapest ways to purify your water, boiling is a tried and true method that’s been used for many, many years. Bacteria and other microorganisms are unable to survive in temperatures that exceed the boiling point, so you’ll be able to drink water from most sources with confidence. However, that doesn’t mean you can get away with everything. Boiling will kill organisms that are alive, but it won’t do anything to remove chemicals like arsenic, chlorine, lead, mercury, and many more that can harm your health. So while this method is far better than doing nothing at all, still be cautious about where you’re getting your water from, and use some of the other water purification methods listed below when possible.

To begin the process, grab a pot and fill it with water from a source of your choice. Do your best to ensure that the water is as clean as possible – boiling may kill bacteria, but it won’t remove dirt!

Next, start a fire, since you’ll need a heat source to bring the water to a boil. If you’ve never made a campfire or it’s been a long time, check out our guide on how to build a campfire! A propane burner or stove would work for this task as well.

Place your pot over the fire, and keep it there until you see the water come to a rolling boil. It’s only then that you know it’s been heated up sufficiently to kill the microorganisms inside.

Allow the water to cool down to a safe temperature, pour it into your bladder or cup, and enjoy!

2. Purification Tablets

tablets against a blue background

If you don’t have the necessary resources to boil your water, consider looking into water purification tablets. In fact, these are great to have anyway, because sometimes you’ll run out of water well before you find yourself in a good position to start a fire. To avoid getting dehydrated in this instance, just fill up your water bottle or bladder and drop in a couple of tablets. You’ll have drinkable water within a few minutes.

Most tablets have a mix of iodine, chlorine, and chlorine dioxide, which together create an environment that kills bacteria and viruses. They’ve been proven safe and effective for everyone, unless the individual has an allergy to one of these ingredients or has trouble with their thyroid.

Backpackers like to carry tablets on them because they’re small, lightweight, and do their job well. No matter where you draw your water from, there’s a possibility that you’ll encounter dangerous microorganisms, so it’s important to use these tablets every time you refill your water supply. The number of tablets that you need to use will vary depending on the brand that you purchase, and it’s vital that you get the amount correct. Too little won’t be effective in killing the pathogens, and too many will turn your water acidic.

Once you’ve added the tablets, give your water a good shake to thoroughly mix in and dissolve the purifying agent. Then, the recommended waiting time is about 30 minutes before it’s safe to start drinking.

3. Filtration

water filter bottle on a rock

By far my favorite way to purify water, filtration bottles are products that I swear by for my own personal use. Specifically, I love Grayl’s ultralight water filtration bottle, and have used it to safely drink from various water sources all over the world. You can check it out here!

The bottles aren’t as cheap as the other options listed above, and you will need to replace the filters from time to time, but I believe they’re the most effective way to remove harmful substances. Plus, unlike boiling water or adding purification tablets, once the water has passed through the filter, it’s perfectly safe to drink. There’s no need to wait for the water to heat up and cool down, or for the tablets to finish their job.

Many filtration bottles are also effective at removing various metals and chemicals that can be found within water sources, which is something that can’t be said for the previously mentioned methods of purification. And they’re still just as good at removing any pathogens as well.

Different filter bottles are used in different ways. Some require you to fill the bottle up, and then push the filter through it, kind of like how a French Press is used for coffee. Others simply have you fill the bottle, and it’s filtered as you suck the water through a straw. Whatever option you go with, these products are easy to use and well worth the money.

4. Distillation

water splashing in a bucket

Most of the time when you’re camping, you’ll have access to freshwater lakes or rivers. These are the sources that you’ll want to draw from most often, but sometimes they aren’t always available. For example, what do you do when you’re camping on a beach, and the only water source within several miles is the ocean in front of you? We all know that it isn’t safe to drink salt water, so does that mean there’s no choice but to pack in all the water you’ll need?

Not exactly.

Through the process of distillation, it’s possible to convert saltwater into drinking water through a few easy steps. That way, no matter where you are in the world, you won’t have to worry about running out of water to drink.

First, make sure you have a pot with a dome shaped lid. Fill the pot with water, and place a cup inside it as you start bringing the water up to a boil. Place the lid upside down on the pot, with the handle pointed downward into the cup.

As the water boils, it will be turned into steam. This will condense and slide down the curved lid into the cup that you placed inside. Once all of the water has evaporated, there won’t be anything left in the pot except for salt, leaving you with fresh drinking water in your cup. Give it some time to cool down, and enjoy your fresh water.

5. Solar Water Disinfection (SODIS)

plastic water bottle lying on the ground

A relatively new way to purify water, solar water disinfection makes use of the sun’s ultraviolet rays to kill microorganisms. To use this method, all you’ll need is water and a plastic bottle. Just keep in mind that this is a slower way to clean your water, and can only be used on smaller amounts at once.

Start by filling your bottle with any amount of water between 0.3 to 2 liters of water. Shake it up thoroughly to allow the water to oxygenate, and then leave it in a sunny spot to sit. If it’s being exposed to direct sunlight, it should be safe to drink after about 6 hours. For cloudy days, it’ll take significantly longer – expect to wait 2 days before you can confidently drink.

While useful if you’re dangerously low on supplies, most of you likely won’t need to use this bushcraft technique. The other methods listed above will be better able to suit your needs when you need to refill your reservoir.

6. Ceramic Water Filter

These water filters make use of the holes found in ceramic materials, allowing water to pass through, while blocking particles of dirt, microorganisms, and bacteria. They work exceptionally well, aside from the fact that the ceramic pores are big enough to allow viruses through. If you’re unsure about the quality of the water source, I’d recommend passing it through a different type of filter, just to be safe.

7. Make a DIY Sand Filter

close up of black sand

Hopefully you never find yourself in a situation where you need water but don’t have a filter. If you do, one of your best DIY options is going to be a sand filter.

First, start by grabbing a plastic water bottle, and sawing off the end. Fill the neck of the bottle with pebbles, and pour in a little gravel on top of that – this works to prevent any sand from falling through the opening into your fresh water. And to top it all off, add the sand to the rest of the bottle.

When you pour water into the large opening you created when you cut off the bottom of the bottle, it will filter through the sand and gravel until it comes out the end you usually drink from. This process will remove larger particles, helping your water go from dark and murky to crystal clear. If it still looks a little cloudy after being filtered once, keep passing it through the sand until it’s clear.


Water is often the most essential item you can have when you’re enjoying an extended stay out in nature. While usually not too difficult to find, drinking it straight from the source is a bad idea if you want to stay healthy. From naturally occurring bacteria, to microorganisms found in animal fecal matter, there’s a lot to be wary of before you decide to take a sip. To stay safe, use one or multiple of the water purification methods listed above every time you draw water.

Meet the Author!

By the age of 20, Spencer had already tackled some of the most famed mountain ranges in Europe, Asia, and North America. His mission is to help others accomplish their own outdoor-related goals, even within the time constraints of a 9-5 job and a busy life schedule.

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