How to Choose the Right Water Filter for Your Backpacking Trip

Water-borne illnesses are a sure way to ruin your backpacking trip or the weeks afterward, so you're probably going to need a water filter? But which one? We break it down.

Not every body of water will make you sick, but no matter how pristine a natural water source may appear, microscopic threats to your body - including, viruses, protozoa, bacteria, and other nasties like Cryptosporidium cysts - may very well be lingering. Water-borne illnesses are a sure way to ruin your backpacking trip or the weeks afterward.

I used to have the “looks clean, looks good to drink mentality” because odds are e.coli and giardia, among other things, won’t set in on your trip, but the time following when you have returned. I justified taking these risks because being sick at home did not sound too bad to my naivety, but I can tell you from first-hand experience that I regret having had this mentality. Now my water filter is as essential as my sleeping bag or headlamp. There is an entire world out there for choosing a water filtration system, while universal and multi-use options exist, certain locations across the globe call for a unique style of water filter or purifier. The bottom line is it’s important to know where you’re going, and what is right for you.

A waterfall descends over red rocks into a blue pool
Photo by Connor Hult

Water Filters vs. Purifiers: How They Work

Physical water filters utilize a cartridge with microscopic pores that catch any dirt or debris present in the water as it moves from the container past the cartridge. These water filters can vary in styles, but will mostly stay around 0.1 microns for pore size. Because dirty water is being pushed through these filters, gunk will clog them and they will need to be regularly cleaned and eventually replaced. 0.1 microns is a solid standard when choosing a filter that will be rid of most water contamination.

A purifier will rely on either chemicals (commonly iodine) or ultraviolet light to kill any contaminants in the water. The main advantage of water purification is that it will kill viruses, which are generally too small to be caught by the cartridge of a general water filter. Don’t fret - viruses are not typically found in North America, but be sure to check in before you go!

Quick Reference Guide

UV Purifiers

Ultraviolet filters take advantage of the destructive properties of ultraviolet light, by exposing organisms and contaminants, disrupting the DNA, and thus “purifying” not just filtering your water. Purification time varies between models but typically hovers around 60-seconds for a liter of water. These kill viruses but do not take care of sediments or cloudiness in the water. Note that in clean, clear water, the light will not turn on, the water purifier is still functional, you just happened to find pristine water in the wild.

A green-blue pen-like UV water purifier
The Steripen Ultra is a popular UV filter.

Pros

  • Kill viruses via UV light (The majority of filtration methods do not.)
  • Easy to use and water is ready to drink promptly
  • Lightweight
  • The only thing you have to replace are batteries - no cartridges or cleaning necessary

Cons

  • Do not filter out dirt, sediments, or cloudiness - must be paired with another prefilter if desired. (Water is still ready to drink, but you may be flossing dirt out of your teeth.)
  • Reliant on batteries, requiring some due diligence and reliance
  • Not the most durable and ironically the battery assembly is not waterproof
  • Higher volumes of water should be treated by another method for the sake of efficiency

Best Use

UV filters are a great personal filter when traveling abroad or whilst in an unfamiliar geographic region where you don’t know what you don’t know about the water. Clear running water free of sediment (think snowmelt, rivers, and lakes) will not require the use of a prefilter since there will not be sediment present.

Chemical Purification

Although they sound like a contaminant you are trying to rid your water of, chemicals prove to be another useful treatment method. These products are typically iodine or chlorine-based (Aquamira or Potable Aqua are great options). You just drop them in your water container and wait. Although these will kill bacteria, protozoa, and even viruses they do require the use of a prefilter if you want to remove sediments from the water.

Pros

  • Kill viruses (The majority of filtration methods do not.)
  • Easy to apply to bottled water
  • Great compact and lightweight option
  • Can just pop water purification tablets into a hydration pack and filter while you’re hiking
  • Always great to have for emergency preparedness

Cons

  • Do not filter out dirt, sediments, or cloudiness - must be paired with another prefilter if desired. (Water is still ready to drink, but you may be flossing dirt out of your teeth.)
  • Iodine can leave a poor taste in the water
  • Chemicals are consumables and you have to replace them often if using regularly
  • Large quantities of water require more treatment, so a long trip could require multiple bottles/vials
  • Chemical treatment is time-consuming and can take 30 minutes for a 2-liter bottle.

Best Use

Chemicals will treat any bad stuff in the water and serve as great means of treatment for rivers or lakes without many sediments present. Because of their timely nature and one-time use per tablet or treatment, they are the best option for a backup filter, or in an emergency situation whether you're in town or outdoors.

Special Considerations

Iodine is sensitive to light, so do not remove them from their dark bottle to save weight/space - you will render your treatment null. Iodine also breaks down slower in cold water; if your planned area’s water source comes from snowmelt, you will have to wait longer to purify (or just use another alternative).

Boiling

Taking a step back in time gets us to a tried a true method of water treatment: boiling water is traced back to prehistoric times with the discovery of fire. With a stove system (or fire) bring your water to a boil for at least a minute - three if you are above 6000 feet.

Pros

  • Kill viruses (The majority of fast filtration methods do not.)
  • Can do large quantities as long as your pot allows
  • Great backup option that you should almost always have with you while backpacking anyways

Cons

  • Do not filter out dirt, sediments, or cloudiness - must be paired with another prefilter. (If you don’t mind drinking silty water, this will do.)
  • Boiling water is both time-consuming and costly, it requires packing extra fuel to account for so much water and can get on the heavy side rather quickly
  • In addition to waiting for the water to boil, you must also wait for it to cool

Best Use

Boiling is best for situations where you will not need water to be filtered while on the go. If you can afford to wait until camp and have time to spare, this is a great option for doing large quantities of water. Another great use is winter camping where melting snow may be your only option available!

Pump Filters

Pump filters utilize a hose and a pump lever or squeeze mechanism to pull water from the source. These hoses are small and can fit in the smallest seeps and puddles of water, and the speed of the filtration is entirely dependent on how fast you can squeeze your hand or pump the lever. They are great to filter into another container or hydration bladder.

Pros

  • The smallest seeps, puddles, or springs can be accessed with the small nozzle of the pump
  • You can filter the exact amount you need
  • Replaceable cartridges

Cons

  • Pump water filters do not treat viruses (must be paired with a purifier if desired)
  • A fast flow rate is dependant on the pumping capabilities of your hands - which can be a chore
  • Larger quantities can take longer depending on the model (some have a nice pump handle to speed things up)
  • These do not come with their own storage, so you must pump the treated water into another container

Gravity Filters

Gravity water filters provide a lot of water for larger groups. Just set up base camp with one of these guys and come back to liters of clean water, ready to go. A gravity system works by filling your reservoir, finding a place like a tree branch to hang it and let gravity do the work as you wait.

A two-bag water filter system connected by a tube
The Platypus GravityWorks water filter

Pros

  • Best value and most convenient for larger groups. If you want gallons of water, this is your system.
  • Return to treated water ready at your camp - a very low-effort option
  • Replaceable filter element

Cons

  • Do not filter out the smallest viruses, and must be paired with a purifier if desired
  • Treatment takes longer than pumping
  • Hard to fill a reservoir without access to a lake or deeper river stream
  • Heavy and bulky if using for a smaller group

Best Use

Gravity filters are best used for big groups whether camping, rafting, or establishing a base camp - they filter large quantities of water while you’re out and about doing your own thing. They are reliant on a larger water source that is relatively close by because of their larger reservoir size. In smaller groups, they are not the most practical as you will seldom need that much water and can get by with a smaller alternative to save on weight and space in the pack.

Squeeze Filters

Now, these filters may seem to be the same as other bottle filters on the list but one subtle difference makes it a matter of convenience. Just fill up with water and as the name goes, squeeze to pass the water through the cartridge and have it ready to drink. These are quite common and there are many different styles to choose from. The flow rate and size of the reservoir vary depending on which type of filter you purchase.

A man's arm extends out to display a squeeze-filter water filter over a rocky stream
Expert Bobby Chadderton hydrating with a Sawyer squeeze filter. Photo by Bobby Chadderton

Pros

  • Great price on these filters
  • Replaceable cartridges
  • Lightweight and very compact

Cons

  • The life span is dependent on how routinely they are cleaned
  • Do not filter out the smallest viruses, and must be paired with a purifier if desired
  • Water quantity is limited to the container size and large volumes are time-consuming
  • Not as convenient as a ready-to-go bottle filter, since generally you are attaching the filter to the reservoir on each use

Best Use

Squeeze filters will fill most individual's needs. They are a great choice for a small party to have as you can treat water into another container or drink out of the filter itself. They are not ideal for large groups and can be more irritating to clean and maintain.

Bottle Filters

The best value award goes to the bottle water filter. It is my personal choice to always have one on my endeavors outside. Just scoop and drink straight out of the nozzle, or filter into a preferred container. What makes these filters unique is the filter simultaneously acts as a bottle adaptor to be interchangeable with other containers such as a plastic bottle.

A person's hand holds a water bottle filter over some blue-green water
Hydrating between paddles on the way to Mt. Moran in Grand Teton National Park with the Katadyn BeFree filter. Photo by Connor Hult

Pros

  • Long filter life and a great value (a general standard is about 1000 liters of use)
  • Filters out sediment and can be used as a prefilter
  • Can use the filter on multiple bottle/reservoir types, there are even filters that will fit a standard water bottle (these are great for international travel if your included flask breaks)
  • Almost no field cleaning required in comparison to other options
  • Replacement cartridges available
  • Concerning ease of use, there is no other more intuitive option

Cons

  • Do not filter out the smallest viruses, and must be paired with a purifier if desired
  • Water quantity is limited to the container size and large volumes are time-consuming
  • If you skip out on the little maintenance that these do require, they will get clogged with gunk

Best Use

This filter is one of the best lightweight and value options for easy access that takes up little space. Even with a hydration bladder I often fold this up into a side pocket of my trail vest and filter as I run on long days. This is a good option that works for any backpacker, climber, trail runner, or anyone on a day hike for personal use. If filtering for large parties the ideal use here would be for everyone to have their own! This is perhaps the best backpacking water filter out there!

Straw Filters

Straw water filters, made famous by the Lifestraw personal water filter, are very stowable and portable filters designed with carbon or ceramic filters within a straw to make any body of water your personal cup - provides treated water straight from the source to you.

Pros

  • Straw-style filters are incredibly lightweight and easy to store, fitting in the palm of your hand
  • One of the cheapest options on the list - geat for individual needs

Cons

  • If you wish to store water, your only option is getting a straw that is compatible with a water bottle
  • Not every model has replaceable cartridges
  • 1-person filter option

Best Use

Straw filters were popularized because of the novel concept of drinking straight from a stream. They are indeed useful, but the only reason I would pick this option over a bottle or squeeze style filter is cost. They are the cheaper options on the list, you are just limited to drinking straight from the water source and there is no way to pack the filtered water with you. If you are looking for the most lightweight and cost-friendly option - the straw-style filters are your go-to.

One man smiles at the camera while another collects water in a bottle
Stopping for a water break high up on Mount Rainier - running water is more convenient than melting snow. Photo by Connor Hult

So there you have it. A little bit about every type of water filter you could possibly need. Still not sure which one is the right fit for your trip? Chat with any of us here at Curated - we'll help you out.

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Written By
Im an Oregon Native, but have since moved to Bozeman, Montana. Like many here I was drawn by the mountains and accessibility to the outdoors. I spent my adolescence romping around Mount Hood and the Columbia River Gorge. I have since expanded my outdoor pursuits of choice. I’m a big fan of the snow...

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