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Published Aug 31, 2021 1:48 PM

The best water purifiers are reliable, easy to use, and lightweight. It allows the user to quickly remove pathogens from a drinking source and have full confidence that the water is clean. From backpacking to an emergency situation, you’ll find a water purifier system that fits your needs in our top picks.

Even the most pristine waters can harbor diseases. Animal and human waste carry diseases and pathogens such as protozoa, bacteria, and even viruses. With so many choices for water treatments on the market, it’s tricky to know what to select. Get to know what makes the best water purifiers and some of the top filters on the market before investing in one yourself. Using these products can help protect you from disease and discomfort in the wilderness.

Best Backpacking Water Filter: Sawyer Squeeze Water Filtration System

Key Features

  • Weight: 3 ounces
  • Type: Squeeze and/or gravity filter
  • Speed: Filters 1 liter in less than a minute if squeezed

Why it Made the Cut

Convenience, reliability, and cost make the Sawyer Squeeze the overall best backpacking water filter. It is perfect for filtering water from various wilderness sources while on the move.


  • Easy to Use: Just fill the reservoir, twist on the filter, and squeeze
  • Flexible: The standard kit comes available for a quick squeeze or gravity filter
  • Transferable: The filter can be screwed onto many other water bottles, including disposable ones


  • Does not protect against viruses
  • Filter needs to be cleaned

The Sawyer Squeeze Water Filtration System is my pick for the best backpacking water filter, offering a lightweight system that works quickly to remove bacteria, protozoa, cysts, and sediment down to 0.1 microns. It comes complete with two collapsible pouches for collecting water, a 5 x 2-inch filter, a mesh sack, and a syringe to clean out the filter. It also includes the tubing and adapters needed to make it function as a gravity filter. The system weighs in at only 3 ounces, which all but disappears in a crowded pack.

Using this is easy and foolproof, which is one reason why I ranked it so highly. Simply fill the water pouch, screw on the filter, and squeeze. The pressure created by squeezing forces water through the filter and fills a liter water bottle in about 30 seconds. If you want, you can scrap the pouch and use a water bottle (the filter will screw into many disposable water bottles). Maintenance is easy. If/when the filter gets clogged, simply push clean water back through using the included syringe. Recommended cleaning includes rinsing with a water/bleach mixture.

Overall, this is a great choice for both weeks in the woods or as an emergency water system. But it should be noted that while filters such as this one offer protection against bacteria, they do not eliminate viruses. In areas with high pathogen water, combine this filter with a chemical treatment and/or boiling.

Best Water Purifier System: Katadyn Steripen Ultra UV Water Purifier

Key Features

  • Weight: 4.94 ounces
  • Type: Ultraviolet light
  • Speed: Purifies 1 Liter in 90 seconds

Why it Made the Cut

Convenience, reliability, and effectiveness make Katadyn’s Steripen Ultra UV Water Purifier my choice for the best water purifier system. The UV light produced kills the most microscopic pathogens of the units I evaluated.


  • Easy to Use: Just push a button and stir your water for 90 seconds
  • Simple to Operate: Steripen removes chances of human error
  • Effectiveness: Protects against microscopic viruses and other pathogens


  • Does not work on cloudy water (must be filtered first, pre-filter sold separately)
  • Costs 3-4 times as much as a squeeze filter

The Katadyn Steripen Ultra UV Water Purifier is my pick for the best water purifier system. The UV-C light rays that the Steripen creates destroy germs’ ability to make you sick and make water safe to consume quickly with almost no fuss. The package comes with the Steripen, rechargeable lithium-ion battery, and USB charging cord—everything needed to start removing viruses and other pathogens. The whole thing weighs 4.94 ounces, which makes it fairly lightweight. Ditching the cord when heading into the field shaves some weight.

This is the easiest system to use. Simply remove the cap, press the button, and stick the Steripen into a bottle of water. Stir the water source gently to ensure the light contacts the entire contents of your container and remove the pen when the light turns off. That’s it. Cleaning is also simple, involving only a wipe with a clean, dry cloth.

Battery life is one of the few concerns with this product. The Steripen can kill 99.99% of protozoa (including Giardia and Cryptosporidia), bacteria, and even viruses, but only if the battery is charged. The lithium-ion battery is usually good for purifying up to 50 liters of water, so it should last for most typical backpacking trips. It can be recharged from any USB power source, including solar panels, battery banks, laptops, or car chargers. Another potential issue is water clarity. The light can’t kill waterborne organisms if it can’t reach them, so your water source can’t be cloudy. If you usually encounter clear streams, then you’re set. If not, you may have to filter your water a bit to remove sediment. Use Katadyn’s FitsAll or another pre-filter to remove particulates when filling your bottle to ensure the UV light can sterilize it. Besides, you probably don’t want to drink gritty water anyway.

Best Water Purifier for Survival: Potable Aqua Iodine Tablets

Key Features

  • Weight: 3 ounce bottle
  • Type: Chemical Tablet
  • Speed: Purifies 1 quart of water in 30 minutes

Why it Made the Cut

Affordability and reliability make Potable Aqua Iodine Tablets my choice for the best water purifier for survival. They are simple to use and a great backup system for an emergency.


  • Easy to Use: Just drop two tablets in a quart of water and wait
  • Reliable: No breakable parts or complicated mechanisms
  • Affordable: 50 tablets cost less than $10


  • Leaves water with an iodine taste
  • Takes at least 35 minutes for the water to be treated

Potable Aqua’s Iodine tablets are a top choice for the best water purifiers for survival. This chemical treatment comes as a small 3-ounce bottle of 50 tablets, which treats a little over six gallons of water. It’s affordability and small size make it a perfect emergency or backup purification system. Stashing a few bottles with your emergency gear can provide you with a lot of safe drinking water when the chips are down.

Treatment is very simple. Drop two tablets in a quart-sized water bottle and wait 35 minutes. The iodine kills bacteria, viruses, and giardia as it dissolves. You can easily treat more water by adding the appropriate number of tablets. Because the bottle is so small, you can load up your best backpack or bug out bag without weighing it down.

There’s a downside to just about everything, and these water purification tablets are no exception. In an emergency, 35 minutes can be a long time to wait for potable water.  The tablets change the taste and sometimes the color of your drinking water. If you have a particularly sensitive palate, you can pick up the taste neutralizing tablets that Potable Aqua sells to restore the natural taste, odor, and color.

Potable Aqua’s Iodine tablets are used by military and emergency aid organizations worldwide because they purify water cheaply and easily. Even if you have a primary water filtration or purification system already, a bottle or two of these is cheap insurance in the backcountry or in case of emergency. 


My experience with water filtration and purification comes from many years in the backcountry, where I covered hundreds of miles by foot and by paddle, both recreationally and as a guide. Leading groups through the backwoods and waterways of Maine and New Hampshire as a wilderness instructor for the Appalachian Mountain Club illustrated the importance of having a capable water filtration system. I’ve had to purify drinking water from every source imaginable to ensure myself and my participants have a safe and enjoyable backcountry experience. When looking for the best water filter, I evaluate products using the following criteria:

  • Weight and volume: Every ounce in your pack matters on a wilderness trip, so the filter/purifier must be light and packable.
  • How difficult it is to use and maintain: To ensure that no one gets sick in the wilderness, I need to be confident in my own, and travel companions’, ability to use the filter/purifier correctly every time. The product also needs to be easy to clean between uses so it can be effective on the trail.
  • How effectively it removes and/or kills pathogens: The filter/purifier needs to be able to be used in a variety of water sources—from clean to disgusting.
  • Overall cost: Does the filter/purifier provide good value?

Things to Consider When Choosing Water Purifiers and Filters for the Outdoors

When shopping for the best water purifier and filter, there are many factors to consider, from the water source you are drawing from and the pathogens you need to protect against. Think about the following before you make a purchase:

Multi-Day vs. Emergency

The volume of water you’ll need is a key consideration when choosing a filter or purifier. Do you need one just in case you run out of packed water, or are you filtering for multiple days? Gravity and squeezable filtration systems are the favorites of many who spend days in the backcountry without access to clean drinking water; however, these systems tend to be bulky with many components to pack and clean. For those looking for an emergency water treatment, a small and packable straw or an emergency chemical treatment might be the best choice.


The price of water purifiers and filtration systems varies wildly depending on the model you choose. The cheapest option is usually a chemical treatment. These also tend to be the smallest, which is why it is often brought on a trip as an emergency and/or backup purification system. UV purifiers are usually the priciest but are small and convenient. Water filter systems—including straw, pump, gravity, and squeeze—fall into the middle pricing category.


Another consideration is the types of water sources you will encounter and how fast you need the water to be purified. Squeeze and straw systems are convenient for filling in rushing mountain streams and rivers and can be almost instantly filtered into your mouth or water bottle. Pump and gravity filtration systems are great for standing water and large groups/high volume needs. Lastly, a UV system is extremely convenient due to its almost immediate purification and packable size.


Q: Are water purifiers effective?

No water purifier is effective against 100% of pathogens and diseases, but most of them do an excellent job at removing the most common threats to water in the wilderness. Water filtration removes particulates and most bacteria and protozoa, while water purifiers like UV and chemical treatments can also treat viruses. If your water source is particularly contaminated, consider using a combination of products to make it most effective.

Q: Do all water filtration and purification systems protect against the same things?

No. Generally, water filters protect you against protozoa and bacteria but cannot filter out tiny viruses. Water purification systems, like UV and chemical treatments, also kill viruses.

Q: How do I know if I need a purifier vs. a filter?

A filter system (like the Sawyer Squeeze) is perfectly adequate in the US and Canadian backcountry, where the main concern is microorganisms spread through animal feces in water. Viruses are more often spread through human fecal matter, so if you are drawing water from a heavily trafficked area, choose a purification system like the Katadyn Steripen.

Q: Can’t I just boil my water?

Yes! To purify your water, bring water to a roaring boil for three minutes. This effectively kills all pathogens. The challenge can be that it requires access to a stove and uses fuel.

Final Thoughts

The best water purifiers for your outdoor ventures will vary based on your needs and the water sources you’re likely to encounter. Given the wide variety of scenarios I have encountered, the Sawyer Squeeze is my choice for the best backpacking and camping water filter. It is affordable, reliable, easy to use, and provides you with great-tasting filtered water.