How to Purify Water on the Trail (8 Easy Ways)

Miles logged, blisters earned, memories made—that’s the hiking life. But staying hydrated on the trail isn’t always sunshine and rainbows.

At moderate altitudes, hikers lose significant water: up to 1.9L daily for men, 850mL for women, plus increased urine output. [1] The real challenge? Finding safe or purifiable water.

Over time, I’ve tested various water purification methods – some fancy, some basic – all in search of the most efficient way to get clean water on long hikes.

This guide is your shortcut. We’ll explore turning murky trail water into safe drinking water, identify unsafe sources, and discuss the best practices to protect water sources.

Boots laced, bottle grabbed? Let’s learn how to decontaminate water on the trail!

Also, check our hydration calculator to know how much water you need while hiking.

What is the Best Way to Purify Water in The Wilderness?

The best way to purify water in the wilderness is through a combination of methods like boiling, filtering, and using water purification tablets. These steps help eliminate harmful bacteria, parasites, and contaminants, ensuring safe drinking water during outdoor adventures.

If you were wondering which water purification methods work best, here are your options:

1. Using Water Filters

Water filters are different from water purifiers through their mechanism. While purifiers rely on chemicals or UV light to kill microorganisms, filters simply sieve them through very fine media. There are 5 types of filters you can use to decontaminate water on the trail:

(a) Pump Filters

These workhorses use manual force to push water through a fine-mesh filter, effectively removing bacteria, protozoa, and even some parasites (think giardia).

I recommend choosing one that has been EPA certified, as they are the only ones to guarantee protection against 99.9999% of waterborne bacteria and 99.9% of protozoa cysts.

I used one for water treatment on my John Muir Trail trek, and even with questionable water, it delivered clean, confidence-boosting hydration.

PROS

Ideal for murky or questionable water sources, offering peace of mind for even the most cautious hiker.
Built to withstand the bumps and bruises of trail life, ensuring reliable performance even in tough conditions.
Can handle various water sources, from lakes and rivers to treated water sources that may still have trace contaminants.

CONS

Compared to other options, they take up more space in your pack, adding weight and bulk to your gear.
Pumping requires effort, especially for larger quantities of water. Depending on the model, it can be tiring after a long day on the trail.
Regular cleaning and filter replacements are crucial for optimal performance and safety.

(b) Gravity Filters

If you are not a big fan of manual work, this option utilizes gravity to pull water through a filter media, like activated carbon or ceramic elements.

Think of it as setting up a mini waterfall in your campsite, with clean water collecting at the bottom. Remember using one on a Yosemite backpacking trip – it was the easiest way to purify water! Fill, hang, relax, and enjoy clean water without breaking a sweat.

PROS

No pumping is required.
Compared to pump filters, they’re more pack-friendly, saving precious space and weight for other essentials.
Can filter large quantities of water at once, perfect for groups or refilling multiple water bottles quickly.

CONS

Takes longer than pump filters, especially with larger volumes.
Not ideal for highly turbid water or sources with the potential for larger debris, as they can clog the filter media.
Be cautious in freezing temperatures as the filter media can be damaged, rendering it unusable.

(c) Bottle Filters

One of the simplest ways to clean water is to screw a bottle filter onto a disposable water bottle, transforming it into a mini filtration system. Simply dip the bottle in your water source and sip away – but be mindful of the source itself!

PROS

They take up minimal space and weight.
Ideal for on-the-go water access during short hikes or day trips.
Generally, a budget-friendly option.

CONS

Primarily remove bacteria and protozoa, not suitable for heavily contaminated water sources like stagnant ponds or muddy streams.
Slower than other filters, especially with thicker liquids like algae-laden water.

(d) Squeeze Filters

Like pump filters, these models use muscle power, but in a different way. You fill a bag of water and then squeeze it every time you need a sip. This way, you force water through a fine mesh, trapping nasty bacteria, protozoa, and sometimes even parasites.

PROS

Ultra-compact and lightweight.
Handle various water sources, from murky streams to treated water with trace contaminants.
Built to withstand the rigors of the trail.

CONS

Squeezing can be tiring, especially for large quantities.
Slower filtration, especially with thicker liquids.
You need to replace filters regularly.

(e) Straw-style Filters

These are essentially straws with built-in filters. Simply dip the straw in your water source and sip. They’re ideal for quick hydration on short hikes or with relatively clean water.

PROS

Clip onto your pack or fit in your pocket, taking minimal space.
Perfect for on-the-go access and instant refreshment during short hikes or day trips.
The best way to filter water while on a budget.

CONS

Primarily remove bacteria and protozoa, not suitable for heavily contaminated sources.
Even slower flow rate than squeeze filters.

2. Using Water Purifiers

While filters are great for tackling bacteria and protozoa, sometimes you need a heavier weapon in your water treatment arsenal. Enter water purifiers, designed to eliminate virtually all waterborne threats, from viruses to chemicals.

(a) Chemical Purifiers

They typically use chlorine dioxide or iodine tablets to kill microorganisms and are effective against a wide range of waterborne pathogens. For me, chlorine tablets were a lifesaver on a multi-day trek in Nepal, where clear water sources were scarce.

I really appreciated the peace of mind they provided despite the slightly medicinal aftertaste.

PROS

Eliminate viruses, bacteria, protozoa, and even some parasites.
Easy to carry in your pack without adding significant weight.
Simple to use – drop a tablet, wait, and enjoy clean water.

CONS

Can leave a slight chemical aftertaste, which may not be everyone’s cup of tea (literally).
Waiting time after adding the tablet can range from 30 minutes to several hours.
Tablets can expire, so check before heading out.

(b) Ultraviolet (UV) Purifiers

These purifiers use UV radiation to disrupt the DNA of microorganisms, rendering them inactive.

PROS

They purify water instantly, no waiting time.
No taste alteration or residues left in the water.
The UV bulb can last thousands of treatments, reducing waste.

CONS

Compared to chemical purifiers, they take up more space and weigh more.
Require batteries or a power source.
May not be effective in cloudy water, as particles can shield microorganisms from UV light.

3. By Boiling Water

Among the natural ways to purify water, boiling is a tried-and-true method that requires no fancy gadgets, just a pot and a heat source.

Now, I’m not saying it’s always the most convenient option, but for its reliability and effectiveness, it deserves a spot in every adventurer’s toolkit.

Here’s the lowdown on boiling:

Find your heat source: Whether it’s a camp stove, a campfire, or even collected wood, ensure it’s reliable and strong enough to boil water.
Fill your pot: At higher altitudes, you need to boil for longer durations, so factor that in when choosing the amount.
Bring it to a rolling boil: This means visible, sustained bubbles throughout the water, not just around the edges. Aim for:

1 minute at or below 6,500 feet (1,981 meters)
3 minutes above 6,500 feet (1,981 meters)

4. Let it cool: Patience is key! Don’t guzzle scalding water. Store it in a clean container and wait until it cools to a safe drinking temperature.

PROS

Kills virtually all waterborne pathogens, including bacteria, viruses, and parasites.
No complex equipment or instructions needed, just basic fire skills.
Unlike some chemical treatments, boiling doesn’t alter the taste of water.

CONS

Waiting for water to boil and cool can be frustrating, especially when you’re thirsty.
If using a camp stove, you need to carry enough fuel, adding weight to your pack.
Boiling large pots of water takes more time and fuel.

Bonus Tip: If you’re unsure about the water source’s cleanliness, consider adding purification tablets after boiling for extra peace of mind. Remember, safety first!

References:

https://www.mdpi.com/1660-4601/20/4/3186
https://www.mayoclinic.org/diseases-conditions/giardia-infection/symptoms-causes/syc-20372786
https://www.who.int/news-room/fact-sheets/detail/drinking-water