Best Hiking & Backpacking Water Purifiers of 2021

Last Updated: January 2021

Written by: Opt Outdoor Staff

Having access to clean drinking water is critical for enjoying the outdoors.  We have put together this guide on the best water purifiers to help you stay safe and healthy on your adventures.

Quick Recommendations

TL;DR - Here is a breakdown of the types of purifiers and our recommendations -

Purifier Type

Price Range

Easy to Use

Lightweight

Best Choice

Pump Filter

$350

No

No

Gravity Filter

$30 - $130

Yes

No

Straw Filter

$30

Yes

Yes

Bottle Filter

$60 - $90

Yes

Yes

UV Light

$65 - $110

Yes

Yes

Chemicals

$8 - $15

Yes

Yes

Boiling

$0

No

No



Why Do We Need to Purify Water? 

Water and hydration are essential components of a safe and enjoyable hike into the backcountry.

When you travel out past the point where potable water is available, you’ll need to replenish your supply from natural sources such as lakes, rivers, ponds, and shallows.  

And while it may look idyllic, clean, and pure; hikers who drink untreated water from natural sources are exposing themselves to waterborne pathogens such as -

  • Protozoa - such as Cryptosporidium parvum and Giardia lamblial;
  • Bacteria - such as E. coli, Salmonella, Campylobacter, and Shigella; or 
  • Viruses - such as Hepatitis A, rotavirus, and norovirus.

Protozoa and bacteria can cause gastrointestinal illness leading to diarrhea, vomiting, fever, and cramps.  

Viruses, according to the CDC, can cause all of the above as well as more severe conditions such as encephalitis, meningitis, myocarditis, and hepatitis.

Do We Need to Purify Water when Hiking in North America?

Indeed, waterborne viruses are more commonly associated with developing countries as opposed to North America.

However, as the vast majority of contaminates, both bacterial and viral, are caused by human and animal fecal waste, prudent hikers should always be aware of the dangers.  

And based on how easy and relatively affordable protecting yourself is, it only makes sense to protect yourself as completely as possible.

To that end, we’ll focus on rendering your water safe against bacteria, protozoa — and viruses.

Mountain stream

What is the Difference Between Filtering and Purification?

Purifying and filtering are two terms that are commonly, but incorrectly, used interchangeably.  Here is the nitty-gritty. 

Water filtering removes protozoa, bacteria, and sediment — but not viruses.  

Water purification removes protozoa, bacteria, and viruses.  


Best Water Purifiers for Hiking & Backpacking

This is where things get complicated. There are a lot of different products targeted to hikers. We have read the research and tested the products to provide this guide to the safest and most practical ways for hikers to keep themselves safe.

Purification methods typically fall into the following categories - filters, UV light, chemical additives, and boiling

Each method has its pros and cons, so it comes down to personal preference, budget, pack space, purpose, hike duration, and terrain. Let's look at the options one-by-one.

Filter Purifiers

Filter purifiers utilize microscopic pores to strain out microbes. 

The primary determinant of a filter's effectiveness in removing microbes is the pore size.  To remove viruses the pore size needs to be < 0.01 µm. These are known as ultrafilters.

Portable ultrafilters are most commonly classified as either pump, gravity, bottle, or straw types. 

Pump Water Purifiers

Price Range: $350

Best Suited For: Camping; Backpacking in developing countries; Group hikes.

To use a pump purifier, you place one end of the hose in the water source and the other end in your water bottle. Then through grinding the pump, water is pushed through the filter. 

Pros: 

  • Able to filter and purify large volumes of water; 
  • Allow you to retrieve water from relatively shallow sources; and
  • The internal filter is generally replaceable.

Cons: 

  • Pumping can be a chore;
  • There are moveable parts that can break;
  • Cleaning in the field is required;
  • They weigh more than other methods; and 
  • Can be expensive.

Best Pump Water Purifier

#1

The MSR Guardian is currently the only pump filter on the market that also purifies.  It might be overkill for North American hikes, but it is our top recommendation for backpacking in developing countries.  


Weight: 17 ounces

What we like:  Durable construction; can purify 2.5 liters per min; self-cleaning.

What we don't like:  Heavy on the wallet and in the pack. 

Also, check out: MSR MiniWorks EX Purifier System.

The much smaller, lightweight, less expensive little brother of the MSR Guardian Purifier.  Do note that this model is a filter that comes with Aquatabs for purification. 

Gravity Water Purifiers

Price Range: $30 - $130

Best Suited For: Camping; Group Hikes, Backpacking in developing countries.

Removing the need for physical exertion, these purifiers use gravity to push the water through the filter. 

There are several different configurations and styles to choose from. Some are a two-bag design while others drain directly into a receiving container such as a water bottle, canteen, bladder, or pot. 

To use, simply fill the “dirty water” bag with wild water and position it above the “clean water” bag or container and let gravity do the work. 

Pros: 

  • Relatively easy to operate;
  • Can filter/purify large amounts of water; and
  • No moving parts to break or malfunction.  

Cons:

  • Difficult to fill the bag from shallow water;
  • Typically too bulky for day hikes; 
  • Need a place to hang the bag;
  • Slower than pumping; and
  • Field cleaning of the element is required.

Best Gravity Water Purifier

#1

LifeStraw has a strong reputation in the water purification space, and the Mission Gravity Purifier does not disappoint. Due to the size and weight, it is more suited to camping and group hike usage.


Weight: 13 ounces

What we like: Roll-top dry bag is compact; can filter/purify large quantities of water quickly; easy to clean and maintain.

What we don't like:  Tendency to clog if not cleaned regularly.

Also, check out: RapidPure Trail Blazer Gravity Purifier.  At 18 ounces, this filter is heavier than the LifeStraw Mission but comes in slightly cheaper. 

Bottle Water Purifiers

Price Range: $45 - $90

Best Suited For: Day hikes; Backpacking

For simplicity, it is hard to go past bottle-type purifiers.  Typically, they either use a squeeze or coffee press mechanism to push the water through the filter.  However, what you gain in simplicity and portability you lose in effectiveness.  You get the water in your bottle, and that’s it—no storing larger capacities for future use.

As a result, bottle filters are not great for group use or cooking in camp (we prefer the efficiency and effectiveness of gravity and pump filters instead). But for ultralighters and those on shorter day trips, a bottle filter is a great option.

Pros: 

  • Lightweight and packable;
  • Easy to use;
  • Convenient for single-person use;
  • Great choice for day trips.

Cons: 

  • Slow to filter;
  • Only purify small amounts at a time;
  • Not efficient for groups or cooking.

Best Bottle Water Purifier

#1

The Grayl Ultralight Compact Purifier is a mainstay for a good reason. Simple to use, highly portable, lightweight, and durable.  The replaceable purifier cartridge is good for 300 uses before needing replacement.


Weight: 10.9 ounces

What we like:  Easy to use and clean; highly portable and lightweight.

What we don't like:  Small bottle size; needs regular cleaning.

Straw Water Purifiers

Price Range: $30

Best Suited For:  Day hikes; Backpacking

Straw water purifiers use the sucking pressure created to pull the water through the filter.  Due to their lightweight nature, straw filters are popular with day hikers and for other outdoor pursuits that don't allow the individual to carry a lot of water.

Pros: 

  • Easy to use;
  • Lightweight;
  • Relatively inexpensive.

Cons:

  • Only a single-person treatment option.
  • Cannot store water;
  • Field cleaning is required. 

Best Straw Water Purifier

#1

The RapidPure Pioneer is one of the few staw-type purifiers. Weighing in at only 2.6 ounces and priced competitively makes this a good lightweight and easy option.


Weight: 2.6 ounces

What we like:  Easy to use; very lightweight; good price.

What we don't like:  Replacement cartridges are quite expensive.


Ultraviolet Light Purifiers

Price Range: $65 - $110

Best Suited For: Camping; Backpacking; Emergency kits.

Ultraviolet Light (UV) purification is best used in conjunction with a filter.

This is because while UV is effective in treating bacteria and viruses, UV does not deal with chlorine, heavy metals, VOC's (Volatile Organic Compounds), sediment, Giardia lamblia cysts or Cryptosporidium parvum oocysts.

Another reason to use UV in conjunction with a filter is because UV is ineffective to useless when treating cloudy or turbid water. 

UV doesn’t remove anything from the water. It kills the DNA of bacteria and viruses, so they can’t reproduce after you ingest them. The best UV light protocol is to filter the water into a bottle or other container, then sterilize with the UV light. 

UV lights are easy to use, lightweight, take about 60 seconds to do the job, and are very effective, especially when used in conjunction with a filter. If supplying water for a large group, probably best to have everyone have their own personal UV light and source water from a main filter.

Pros:

  • Quick & easy;
  • Highly effective;
  • Lightweight;
  • No cleaning or replacements are needed.

Cons: 

  • Water should be prefiltered;
  • Cannot know if devices are delivering required UV doses;
  • Batteries required; and
  • Not good for purifying large quantities of water.

Best UV Water Purifier

#1

The Katadyn Classic 3 Water Purifier with Prefilter is the updated version of the Classic.  Removing one of the cons of UV purifiers, this version comes with a prefilter to clear debris from water. The main downside is that you need to carry spare batteries and make sure the battery compartment is kept dry.


Weight: 6.3 ounces

What we like:  Easy to use; lightweight; comes with prefilter; purifies up to 150 liters of water.

What we don't like:  Need to keep battery case dry; burns through batteries quickly so need to carry spares.

Also, check out: SteriPen UltraLight UV Water Purifier.  At only 2.6 ounces, this version is great for travel or emergency preparedness. Rather than using batteries, it is USB-rechargeable.


Chemical Purification

Price Range: $8 - $15

Best Suited For: Day hikes; Camping; Backpacking; Medical kits.

Chemical Purification is a relatively inexpensive and easy method of purification.

Products such as Potable Aqua are available as either Chlorine Dioxide tablets or Iodine tablets that kill bacteria and viruses. They take up no space and weigh practically nothing.

When using iodine, you must allow it to work for at least 30 minutes to reach full effectiveness. The only real drawback to iodine tablets is the limited shelf life (6 months) once the bottle is open, and some people dislike the taste. But at a price of around $8 per bottle, to treat 25 quarts, it’s affordable by most standards.

For chlorine dioxide, you must allow the product to work 4 hrs to reach full effectiveness. And that’s the only real downside to Chlorine Dioxide. If stored properly, it has a shelf life of up to 4 years. And fewer people seem to dislike the taste. It, too, is around $8 per package and treats 20 quarts. 

Pros:

  • Easy to use;
  • Inexpensive; 
  • Good to have as a backup in case other options break.
  • Lightweight.

Cons: 

  • Wait time ranges from 30 minutes - 4 hours;
  • Limited storage life (iodine); 
  • Chemical taste.

camping stove cooking food

Boiling

Last but not least, just boil it. 

According to the United States Center for Disease Control (CDC), the best, safest, and the most fool-proof method by which to kill everything in natural water is to boil it. Bring the water to a boil for 1 minute. At altitudes above 6,562 feet (2000 meters), boil for 3 minutes.  

The disadvantages for hikers is that you obviously must have a heat source such as a campfire or stove and a pot in which to boil the water. And making fire or setting up a stove, boiling water, and letting it cool takes time.

Pros: 

  • Safest method; and
  • Relatively simple and easy.

Cons: 

  • Requires a lot of equipment;
  • Need time to make a fire and let the water cool down; and
  • Difficult to purify large quantities.

This can be a fine method for those who are backpacking or car camping but may not be a suitable option for day hikers. Regardless, it’s a skill you should want in your back pocket should the need ever arise.



Key Takeaways

As with most outdoor and camping equipment, which type of water purification system is right for you is a matter of personal preference. Each person must decide for themselves what’s right based on budget, duration, and frequency of outings, weight requirements, and even physicality.  

We can tell you that there are too much enjoyment and satisfaction to be had in the great outdoors to have it ruined by a virus.  Purifying against viruses — even if you are in North America — buys you peace of mind.

Perhaps you’ll opt for an inexpensive filter and purify the result with iodine/chlorine dioxide. Maybe you can afford a top of the line purifier. Either way, buy the best purification solution you can afford, and it will pay years of dividends in the form of enjoyment, adventure and, fond memories.

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