Best Backpacking Water Filter – How to Choose

Havasu Rock Falls
Like many remote areas in the United States, the water at Havasu’s Rock Falls looks clean, but horses are stabled upstream so the water needs to be filtered.

Filtering and/or treating water in nature is essential for keeping your pack weight down and being able to do a trip that is more than a night or two long. Water is heavy and humans need a lot of it to survive. The best backpacking water filter will not only help save you weight in your backpack but it will make your water taste better and it will protect you from bacteria and protozoa.

Classification and Rating

Best Backpacking Gear
It is hard to imagine that this is what we have the potential of packing into our backpacks.

We classify gear in this article as necessary but also give it a rating. Water purification and even filtering aren’t essential to backpacking but they do protect your health making them necessary in our opinion. Our A-F rating is to help newcomers to backpacking know where to best spend their budget. A quality filtration system can last you a lifetime but the filters themselves will need to be replaced relatively often. The best backpacking water filter will balance the need for a high filtration rate of bacteria and protozoa, a high flow rate, and remain light-weight. Check out our best backpacking gear post to see how we rank and rate all backpacking gear in one place.

The Best Backpacking Water Filter

  • Classification: Necessary Gear
  • B-Rating: Prioritize weight savings and design on a quality product if you can.

Backpacking water filters come in many shapes and sizes. What kind of filter you need is going to come down to preference as all have positives and negatives associated with them. Almost all water filters have a 99.99% – 99.99999% effectiveness in filtering out protozoa and bacteria. So at worst you have a 1 in 10,000 chance of catching one of these when using a water filter while backpacking.

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Best Backpacking Water Filter: Katadyn Gravity Filter
The Katadyn gravity filter can easily be hung from a branch and filter clean water directly into a Camelbak water reservoir.

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Gravity Filters

Katadyn BeFree 3L -  best backpacking water filter
A Katadyn BeFree 3L gravity filter consists of a “dirty water” bag, the blue filter, a clean water hose, and the carrying bag.

Gravity filters are my preference because I do not like to make things unnecessarily complicated. A gravity filter requires the user to capture the dirty water in a bag and then hang the bag up and allow gravity to pull water through the filter. It doesn’t get much easier than that. The downside of a gravity filter is that filtering water can be slow, especially as the filter ages. Most people who experience problems with gravity filtering aren’t backflushing their filters properly after each use. Backflushing or swirling in the case of the Katadyn filter we use, keeps crud from solidifying and clogging up your filter.

Katadyn BeFree 3L (Backcountry, REI)

We love our Katadyn BeFree 3L Filter because it is easy to use and easy to clean in nature (swirling after each use). It also weighs almost nothing (3.5oz) and it has a hose that is designed to connect directly to a water reservoir. Many gravity filters come with two bags; a “dirty” water bag and a “clean” water bag. The idea is to capture the clean water and then use it as necessary. The fact that our water reservoirs can be used for clean water means one less piece of gear to haul around, keep up with, and clean. Katadyn also says you can use the BeFree system like a squeeze filter if you are in a rush and do not want to wait on gravity to do the job.

Tips for Maintaining Your Gravity Filter

One of the biggest complaints of the BeFree System (and all gravity filters) is that it clogs over time. We have found this to be true if you aren’t diligent in keeping your filter clean. We have developed a three-part system that keeps our filter flowing smoothly throughout our typically long backpacking season. First, we attempt to only collect water from fast-flowing sources. Stagnant water tends to have more contaminants that can easily clog gravity filters. If we have no other choice we have collected from stagnant sources but are extra diligent in cleaning the filter immediately after.

Secondly, after each day’s filtering, we will pour about 5% of our clean water back into the filter bag and swish the filter in this clean water rather than a dirty water source. This helps to knock impurities out of the filter without introducing new containments. This is especially helpful on longer journeys.

The third step comes upon returning home (to our truck camper), we will fill our camping mug (after cleaning it) with clean water and soak the filter for 24 hours. Then fill the bag and swish the filter one final time before setting it out to dry and storing it away for the next trip.

6L or 10L Base Camp Pro

The only downside of the 3L is that it is a bit small considering we are usually refilling two 3L Camelbak reservoirs. The opening to capture water is also small. The larger 6L or 10L Base Camp Pro is nice because the opening to capture water is larger. The weight increase is minimal but the filter seems to be slightly inferior to the 3L model. That being said the 6L and 10L also have an aftermarket showerhead so this can double as a solar shower in the backcountry.

Squeeze & Straw Filters

Squeeze filters are usually attached to a water bag and then the bag is squeezed forcing the water through the filter and into another container or directly into one’s mouth. A straw filter essentially does the same thing except the person using the device sucks the water from the “bad” water holding device through the filter for direct consumption. These are fast ways to filter water and the filters are usually rated slightly higher at removing bacteria and protozoa than gravity filters. (About 0.00011% better at best.) The downside of both is cleaning the filters. This forced way of filtering embeds particles deeper into the filters that then must be forced out by backflushing or replacing the product more often.

Sawyer Squeeze

The Sawyer Squeeze (REI) is consistently rated as the best squeeze filter. If you do choose the Sawyer Squeeze make sure you are back-flushing after every use. These filters are known to clog up fast.

Life Straw

The LifeStraw (REI) is an interesting concept as you filter/consume as needed. The downside is that most backpacking trails won’t have water readily available around every turn. So without carrying around several Life Straw bottles I don’t see them as very useful on the average backpacking trip.

Pump Filters

Pump filters are the classic way of filtering water when backpacking. The mechanical pump forces water through a filter. This would seem to be a more effective filter. But in reality, they are rated with the same level of removal of protozoa and bacteria as many other types of filters. In my opinion, this is old technology. However, they can filter water faster than a gravity filter and are easier to clean than a squeeze filter, but they are significantly heavier. They also require repetitive manual effort to use. If you want an arm workout after a full day of working out your legs while backpacking, get one of these pump filters like the Katadyn Hiker Microfilter (Backcountry, REI). At 11oz this is one of the lightest and smallest pump filters available.

Pump Filter
Jake using our old pump filter to get clean drinking water. This felt like a backpacking chore.

Water Purifiers

  • Classification: Optional Gear
  • B-Rating: Prioritize weight savings and design on a quality product if you can.

If you are backpacking in a third world country use water purification tablets, drops, or a UV purifier. These are the only way to kill off viruses in the water. The best backpacking water filter will not remove viruses. Tablets, drops, and UV light will typically kill off protozoa, bacteria, and viruses but a filter is still recommended to be used in conjunction with water purification as you will want to filter out particulates before consumption. Do this mostly because of taste, but also because who wants to drink dirty water even if it won’t kill you? In the USA and many first world countries, we are blessed because our lakes, rivers, and streams are all but entirely virus-free so we really only need to worry about bacteria and protozoa which a filter will remove. When traveling make sure you understand the risks associated with consuming water from any source.

Chemical Treatments

There are many different products to chemically treat water. Many make the water taste bad no matter what they advertise. The Aquatabs (Backcountry, REI) taste better than iodine tablets but they recommend waiting for 30 minutes after treatment before consumption.

UV Treatment

Amazingly, UV light kills everything that has the potential to make us sick. The Steripen Ultra UV Purifier (Backcountry, REI) harnesses the very power of the sun to kill off 99.9% of all bacteria, protozoa, and viruses in 90 seconds of use. This particular UV device weighs less than 5oz and is USB rechargeable which is great for keeping it charged while backpacking especially if you have a portable battery. If you want to make sure your water is clean, use this in conjunction with the best backpacking water filter when traveling anywhere in the world.

Protect the Best Backpacking Water Filter

Best Backpacking Water Filter
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No matter which filter you choose, protect it and clean it often. Filters are known to freeze and crack in cold weather so if you are camping in the cold keep your filter inside your sleeping bag to keep it from freezing. If you have any suspicion that the filter may have had the opportunity to freeze and crack, replace it immediately.

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2 Comments Add yours

  1. Wow, great blog. Indeed backpacking water filter are very useful for travelling and this blog contains all the information. Thanks for sharing this.

  2. Pramod says:

    Very often we backpackers ignore the importance of clean water during our backpacking trips. I think it is very important to keep a portable water filter bottle at all times. You wouldn’t want to fall sick after drinking that clean looking water.

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