When it comes to staying hydrated on the hill, there are options beyond water bottles and flasks. Purifying wild water allows you to top-up on the go and means you can carry less liquid to start with. Negating the need to carry much water with you on a trek is a reasonably compelling case in itself.
As a very useful gadget for hikes, we've put together this guide to help you understand what to look for in hiking water filters and purifiers. We've also recommended the best models.
What to look for in water filters and purifiers for hiking
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.
Sterilising and filtering: Some treatments will sterilise water but won’t remove impurities. Others can filter out certain microscopic particles but can’t necessarily be relied upon to remove viruses. Know what water dangers you’re likely to face and choose the most appropriate treatment for those risks.
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?
The best water filters and purifiers for hiking
Lifesystems Chlorine Dioxide Water Purification Tablets

View offer
Unlike typical chlorine treatments, these tablets leave no noticeable aftertaste. They’re light and packable, and while they won’t get rid of particulates in the water, they will kill bacteria, viruses and cysts in water including Giardia and Cryptosporidium.
LifeStraw Personal Water Filter

View offer
This device is used like a straw to filter water as the individual sucks it up, whether drinking water direct from source (such as a pool or river) or water collected into a bottle. It removes 99.9999%, and 99.9% of protozoa, reduces muddiness and weighs just 57g.
MSR TrailShot

View offer
Whether being used to drink direct from the source, or to fill up a bottle or bladder, the hand-pumped TrailShot filters out almost all (99.9%) bacteria, protozoa, and particulates. It can treat 1 litre of water in 60 seconds and is compact enough to fit in the stash pocket of a rucksack.
Katadyn BeFree Gravity Water Filtration System 3L

View offer
Holding 3 litres of water, the BeFree Gravity system is perfect for base camps or larger groups, where it can be hung up and left to do its thing. Using gravity to filter up to 2 litres of water per minute, it removes bacteria, cysts and sediment.
Steripen Adventurer Opti UV Water Purifier

View offer
The Steripen utilises UV light to eliminate bacteria, protozoa and viruses. It doesn’t remove sediment, and the water needs to be reasonably clear for it to work. However, it’s a neat and rapid (90 seconds per litre) alternative to filtering, for which it can also be used as an additional treatment.