Comparing Different Methods of Treating and Purifying Water on the Trail

Clean drinking water is essential when you’re out hiking, bikepacking, or camping, but you often can’t trust your water sources. Kate’s put together a guide to all of the main ways you can treat or purify your water to help you decide which one’s right for you.

I used to be one of those people who simply hung a cup on the outside of their backpack, and set off on a hike. Living in the mountains, surrounded by swift-flowing streams and pristine creeks, I’d casually take a gulp of water straight from the source.

With ‘iron-guts’ and that invincibility that comes with being under 30, I was living a life unfiltered. That was until I got Giardia. After a trip in Kosciuszko National Park, sipping straight from the mighty Snowy River, I found myself in the doctor’s office being told that I’d caught a stomach parasite.

It cleared up with a bit of medication, but I was mentally scarred for life. Since that pivotal moment, I made an unspoken rule to never go hiking without a water filter or purification at hand.

I’ve used or seen most of these methods first-hand on hikes, so I have a pretty good idea of their benefits and drawbacks. You’ll likely settle on an approach that suits your style of adventures (and patience!), but this can change depending on your goal.

Water safety isn’t limited to the pool or swimming hole

Choosing A Water Source

You’ll want to start with the cleanest water you can find, these tips will help you get the best the bush has to offer:

• Look for the clearest water possible, it sounds obvious but scrounging around for less sediment is easier on your filter, you might not have to use it at all!
• Take water from fast flowing sources over stagnant ponds or puddles; pathogens have less time to develop.
• Know your area! Take a look at a map before you head out and you’ll know about landfills or mines that might contaminate your water source.
• Farm animals are kind of gross – avoid farmland watercourses where possible.

Just because it’s clear, doesn’t mean that it’s clean!  | Photo by @jessleenehme

Chemical Tablets & Liquid Purifiers

When I first began cleaning my water, I started with purification tablets. Being a novice hiker, I was unsure where to begin with water filtration, and these were one of the first recommendations from my local outdoor store. 

They’re simple to use; just add a tablet into the untreated water, wait for a specified time, and the chemicals disinfect the water. But I quickly discovered that they weren’t quite my cup of tea. 

During a thru-hike across the Australia Alps, while filling up from an open water tank, I realised that although my water was now free of microorganisms, it still contained the unsettling sight of swimming maggots. 

The ultralight weight, and convenience was a bonus, but I also hadn’t considered the time it took for the water to become drinkable (30 minutes for bacteria and viruses, 120 minutes for cysts like giardia) or the awful aftertaste left behind by the purifying chemicals (some people don’t mind it). 

Katadyn Micropur Forte Water Purifier Tablets – 100 Pack

Weight: A couple of grams
Price: $49.95
Use: Clear Water
Wait time: 30 minutes for bacteria and viruses, 2 hours for giardia

Filtration methods don’t come much lighter than this

Squeeze and Bottle Filters

Just as the name suggests, these are a collapsible pouch or water bottle with an integrated filter. They’re super popular among long-distance thru-hikers as they’re ultra-lightweight, easy to use, and clean water on the go.

The Katadyn BeFree and Sawyer Squeeze were the most common water filters I saw on the Te Araroa (TA) trail last summer. These effectively remove bacteria, cysts, and sediment with a tiny pore size of 0.1 microns, however this small pores also makes them susceptible to blockage. Unfortunately those pores still aren’t small enough to stop tiny viruses, so you’ll have to use tablets as well if that’s a risk where you’re hiking.

The Katadyn BeFree, which I relied on throughout the Te Araroa, is marketed as capable of filtering 1000 litres before needing replacement. In reality, I found myself having to replace it after about 300 litres (60 days on the trail at 5 litres per day). It became significantly clogged even after cleaning, resulting in an unbearably slow flow rate for my impatient self.

Read more: 7 Things I Packed and Used Every Day Thru Hiking the Te Araroa Trail

Katadyn BeFree 1L Water Filtration Bottle 

Weight: 63g
Price: $109.95
Use: Clear water
Flow rate: 2 litres/minute

The manual labour involved with this option is a small price to pay for the lighter weight

Straw Filters

If you’re not ready to part ways with the convenience of that cup hanging from your backpack, then straw filters might be your ideal choice. These ingenious devices allow you to drink directly from a water source, (or cup) with an integrated filter within a straw.

LifeStraw claims to be the original straw filter, initially designed to strain guinea worm larvae using a plastic pipe and cloth, it has now evolved to protect against bacteria, parasites, microplastics, dirt, sand and cloudiness in water. Nevertheless, just like the squeeze filters, the LifeStraw has a pore size of 0.2 microns, making it susceptible to clogging if not regularly cleaned and ineffective against viruses.

LifeStraw Personal Straw Water Filter

Weight: 46g
Price: $41.95
Use: Cloudy water
Flow rate: not advertised

Use the straw alone or pair it with the matching LifeStraw Bottle | Photo by @jessleenehme

Inline Filters

I like to think of these as a subcategory of straw filters, as they operate on the same principle. Inline filters connect into a hydration reservoir and filtration occurs when you suck water through the bladder hose.

This is my current filter of choice, as it’s just constantly connected to my Osprey Hydraulics Hydration Bladder, ensuring that my water is always ready to drink while I hike. So far, I haven’t had any issues with blockage using the MSR Thru-link Inline Filter. It features a two-stage filtration system; the 0.2 micron hollow fibres effectively remove pathogens, particulates, and microplastics (but not viruses), while the activated-carbon component reduces the presence of chemicals, unpleasant tastes, and odours.

Once you arrive at camp, you can conveniently hang up your reservoir and MSR Thru-link to use as a gravity filter!

MSR Thru-Link Inline Micro Water Filter

Weight: 70g
Price: $99.95
Use: Cloudy water
Flow rate: 1.5 liters per minute

If you’re already carrying water in a bladder, this is a small adaptation to make

Gravity Filters

Gravity filters use (you guessed it) gravity to purify water, taking it from a dirty reservoir to a clean one. With the untreated water at the top, gravity will pull the water through a filter cartridge into the clean water bag, and they’ll remove everything but viruses. Honestly, I’ve never been attracted to gravity filters alone, as they’re not great for filtering water on the fly, however the Platypus Gravity Works Complete Kit can be used as a gravity filter, inline filter, or bottle filter, an all-round water clarifying powerhouse.

One benefit of buying a gravity filter setup is the included bags, with markings and hang points. They’re especially useful if you’re filtering water for a group of people and don’t want to fuss around pulling your bag apart and balancing bottles.

Platypus GravityWorks 2.0L Water Filter Kit

Weight: 325g
Price: $249.95
Use: Cloudy Water
Flow rate: 1.5 liters/minute

Gravity filter in action | Photo thanks to Tom Darley

Pump Filters & Purifiers

Pump filters typically have a pump mechanism, a hose, and a filter cartridge. Given their substantial weight, and price tag to match, these are my least preferred choice for hiking trips. That was until a friend introduced me to the Grayl Geopress.

Down at the Snowy River Extreme Race he effortlessly separated the bottom cup of his water bottle, reached out of his kayak to collect water, and reattached the top by pressing down (firmly). In mere seconds, he was enjoying a sip of clean water, all from a water filter cleverly disguised as a drink bottle. They can clean 710ml in just 8 seconds and be used in clean or dirty water; eliminating waterborne pathogens (including viruses!), sediment, microplastics, chemicals, and pesticides, while enhancing the taste, clarity, and odour of the water.

Heavier pump filters can usually produce more force, allowing for finer filters that effectively remove every kind of pathogen, including viruses. If you’re looking for a reliable one-stop-shop they can be worth the weight.

Grayl Geopress Water Purifier Bottle 710ml

Weight: 450g
Price: $169.96
Use: Dirty Water
Flow rate: 5 liters/minute

The ideal option when you need clean water, and you need it fast!

UV Purifiers

By harnessing ultraviolet light to sterilise water through the disruption of microorganism’s’ DNA, the lamp in modern UV purifiers can deliver a lifetime of purification. They’re highly effective against bacteria, protozoa, cysts, and viruses, but much like purification tablets, they do nothing to remove dirt or floaties from water. Unlike purification tablets, they usually only take a minute or two to purify the water, as long as it’s clear enough for the light to penetrate.

While they boast a reasonably good battery life, UV purifiers aren’t ideal on extended trips where spare batteries are hard to come by.

Katadyn Steripen Classic 3 UV Water Purifier

Weight: 178g
Price: $249.95
Use: Clear water
Flow rate: 1 liter/90 sec

Katadyn Steripen Classic 3 UV Water Purifier | Photo thanks to Wild Earth

Which filter or purification method is for me?

Ultimately, the key is to choose a water filter that aligns with your trip and water source conditions, as well as your personal preferences. Many filters don’t deal well with viruses, but they’re not common in many regions. Purification methods aren’t so good with murky water, but in many parts of Australia and New Zealand you can expect the water you find will be pretty clear.

Some people have the patience to watch their water drip, drip, drip through a gravity filter, while others want clean water instantly to quench their thirst, and some are happy to stick to the good ol’ water boiling method. 

Regardless of your method of purifying your water, speaking from experience, prioritize safe drinking water on the trail.

Table of contents image by Tom Darley
Header image by @tim_ashelford