When it comes to staying hydrated on the hill, there are options beyond water bottles. With a water filter or purifier, you can make wild water drinkable, which allows you to top-up on the go and carry less liquid to start with. Negating the need to carry litres of water with you on a trek is a reasonably compelling case in itself.
But the world of portable filters and purifiers for hiking and outdoor use is as murky as the water they allegedly cleanse. This is primarily because there are no mandatory regulations for this market. There are voluntary standards, which we look at further down this guide, but even these aren’t perfect.
LifeSaver Wayfarer - Best in Test
LifeStraw Personal Water Filter - Best Value
Lifesystems Chlorine Dioxide Water Purification Tablets - Best water purification tablets
Katadyn BeFree Gravity Water Filtration System - Best gravity water filtration system
Platypus QuickDraw Microfilter - Best compact water filter
Grayl GeoPress Water Purifier - Best filter water bottle
LifeStraw Peak Series Collapsible Squeeze - Best lightweight filter water bottle
MSR TrailShot Pocket-Sized Water Filter - Recommended
As a very useful gadget for hikes, we've put together a guide to help you understand what to look for in water filters and purifiers at the bottom of this article. First, here's our recommendations for the best models.
The best water filters and purifiers in detail
Best in Test
While many filters or purifiers will remove two out of three when it comes to bacteria,
- Removes cysts, bacteria, viruses, and particulates
- Also reduces chemicals and heavy metals
- Not the fastest flow rate
This device is used like a straw to filter water as the individual sucks it up, whether drinking
- Tiny and weighs next to nothing
- Couldn't be simpler to use
- Unlimited shelf life
- Lasts for 4,000 litres but is, ultimately, disposable
Best water purification tablets
Unlike typical chlorine treatments, these chlorine dioxide tablets leave no noticeable aftertaste.
- No bad tastes
- Removes cysts, bacteria and viruses
- Doesn't deal with particulates
Best gravity water filtration system
Holding 3 litres of water, the BeFree Gravity system is perfect for larger groups or base camps
- Easy way to filter larger volumes of water
- Doesn't remove viruses
Best UV water purifier
The Steripen utilises UV light to eliminate bacteria, protozoa and viruses. It doesn’t remove
- Removes cysts, bacteria, and viruses
- Batteries included
- Very compact and lightweight
- Can't be used in non-clear water
Best compact water filter
One of our bugbears with hydration systems and water filters is a slow flow rate – it’s
- Fast flow rate
- Very lightweight and compact
- LifeStraw Personal Water Filter is considerable cheaper
Lots of nasty things can lurk unseen in sketchy water sources: Hepatitis A, Norovirus, Giardiasis,
- Super simple to use
- Very effective filtering system
- Not the lightest drink bottle
When weight and size need to be kept to a minimum, this LifeStraw bottle/flask/sack gives you a
- Lighter and more compact than solid water bottles
- Long-lasting filter
- Grayl GeoPress has an even better filter
Whether being used to drink direct from the source, or to fill up a bottle or bladder, the
- Small and lightweight
- Simple and reliable design
- Relatively slow flow rate
Water filter and purifier standards
Because the water filter and purifier market is unregulated, it's very easy for products to be all mouth and no substance.
However, some voluntary standards have been set by NSF. The ones to look for are NSF Protocol P231 and NSF Protocol 248. These standards test devices thoroughly for the removal of waterborne pathogens, which is what you want for wild water sources.
This sounds ideal, but there's a hiccup with NSF P231. Testing includes with tap water and water with increased levels of organic matter, dangerous microorganisms and turbidity (more murky) to simulate contaminated wild water. Products don't necessarily have to be subject to the wilderness water and therefore aren't subject to as thorough testing as other products might.
The best way to get a completely clear answer on how a filter or purifier has been tested, is to contact the manufacturer.
The risk of contaminated water can occur anywhere, but increases in certain areas or scenarios. The three types of pathogenic microorganisms filters and purifiers help remove from water are:
- Protozoa: Single-cell organisms that form cysts, and are common in unfiltered water sources.
- Bacteria: Single-cell organisms, but smaller than protozoa that thrive in warmer water.
- Viruses: Parasites that are even smaller than bacteria that propagate in living cells.
The safest places to source wild water from are at higher elevations, above the vegetation line. Here, you are closer to the water source and the risk of contamination is lowest.
Below the vegetation line you encounter farmland, and more wildlife, which increases the level of water contamination (particulates, protozoa, and bacteria). Inside built-up habitation zones are where the risks of unsafe drinking water are highest, especially in developing countries.
What to look for in water filters and purifiers for hiking
Filter vs purifier: Before making any decisions, this is the most important piece of information you need to know. A water filter will remove cysts and bacteria from water. A water purifier will remove viruses as well.
Sterilising and filtering: Some treatments will sterilise water but won’t remove impurities. Tablets can remove bacteria, cysts, and viruses but not particulates, for example. Some filters will deal with bacteria and particulates but not viruses. But there are some purifiers that deal with bacteria, particulates, and viruses, and even other contaminants like heavy metals. Know what water dangers you’re likely to face and choose the most appropriate treatment for those risks.
Weight and bulk: Most water purification options are relatively compact and lightweight, but some are more so than others. It all depends how much water you’re likely to need to purify. A big, heavy filter that takes up as much space in your pack as a large bottle of water may be of limited value on a short day-hike.
Volume of water: Do you only need something that will purify a small amount of water at a time, allowing you to top up your bottle or bladder, or will you need to treat greater quantities of water for multiple drinkers? Some devices are designed specifically for higher volumes, while others are intended for individual use.
Taste: Some chemical treatments, such as chlorine tablets, can give the water an unpleasant taste, making it much less palatable, albeit safe to drink. Chlorine dioxide is much better.
Water storage: Do you need a device that cleans and stores water, or will you be carrying a separate water bottle or bladder into which clean water can be transferred?