A Combat Vet’s Perspective on Bug Out Bag Water Filtration

This is a guest post by David and entry for our non-fiction writing contest.

There is no shortage of products or systems to choose from, but which ones are the best investments? I’ve been doing a lot of research into the packable water filtration systems currently on the market and I’d like to share my findings and opinions. In this post I’d like to try to cover which products successfully filter/purify water of toxic industrial chemicals, viruses, bacteria’s, protozoa, cysts, algae, spores, and sediments, and which do not. Also, some of the pros and con’s of each variety. So, here we go.

Product Group 1A: Katadyn Hiker / Hiker Pro / Vario
These pump style filters have found their way into many bug out bags, and for good reason. They’re simple and effective. There are very few differences between the models listed above, but I’ll highlight the differences here.

Hiker and Hiker Pro $50 – $75 – Fact Sheet / Pro Fact Sheet

The Hiker and Hiker Pro are both decent backpacking filters and they are both fairly reasonably priced if you shop around. In fact, I own the Katadyn Hiker and I’ve successfully used it to pump my canteens and hydration pack full of pond water with no ill effects. The products are compact, light weight, easy to use, and relatively effective, but you assume some risk because the filter media is only capable of capturing particles of 0.3 microns average size or larger. They do leave a slight tinge to the water and if the water is particularly nasty there can be some mild odors or taste left in the water. It probably won’t kill you, but there are better options out there so that in the event you do have to drink water that is potentially contaminated with a virus you won’t contract it, especially post SHTF when treatment will be harder to come by.

  • •Filtration Quality: 0.3 Microns (bacteria, protozoa, cysts, algae, spores, sediments)
    •Filtration Volume: 200gal / 750L (Pro 300gal / 1150L) 1-3 people
    •Filtration Media: replaceable glass fiber media with activated carbon core
    •Filtration Flow: +/- 1 quart / liter per minute
    •Filtered Turbidity: Mildly Tinged / Mostly Clear
    •Filtered Aroma: Very Mild
    •Filtered Taste: Mostly Pure

Vario $75-100 – Fact Sheet

  • •Filtration Quality: 0.3 Microns (bacteria, protozoa, cysts, algae, spores, sediments)
    •Filtration Volume: 528gal / 2000L 1-4 people
    •Filtration Media: replaceable glass fiber media with activated carbon core
    •Filtration Flow: +/- 2 quart / liter per minute (1q/lpm in long life mode)
    •Filtered Turbidity: Slightly Tinged / Almost Clear
    •Filtered Aroma: Slight or None
    •Filtered Taste: Mostly Pure

With the exception of volume, these filters are almost all identical. If you are going to purchase one of these, purchase the most inexpensive version because no improvement in particle size is gained by purchasing the upgrades. The replacement filters (Hiker / Vario) are reasonably priced to stock up on and easily replaceable simply by unscrewing the top discharge lid, disposing of it, and installing a new one (don’t throw it away though because you can drill a hole in the bottom, clean out the charcoal, and reinstall to use the filter system as an unfiltered pump unit as I’ll discuss later). In the end, these are decent products, but make sure you stock up on the filter cartridges if you intend to use it for any extended period of time or buy a Sawyer (if you’re sold on Katadyn’s brand name then upgrade to one of their endurance series products for greater filtration volume).

Product Group 1B: Katadyn Pocket / Combi / Expedition

These pump style filters are designed to support multiple people (anywhere from 1 – 20 depending on variety) or for a longer period of time. They range from on the expensive side to outrageous, but if you have the money they’re awesome. There are some variations to discuss though.

Pocket +/- $270 – Fact Sheet

  • •Filtration Quality: 0.2 Microns (bacteria, protozoa, cysts, algae, spores, sediments, and some viruses)
    •Filtration Volume: 13,200gal / 50,000L
    •Filtration Media: Replaceable Ceramic
    •Filtration Flow: +/- 1 quart / liter per minute
    •Filtered Turbidity: None
    •Filtered Aroma: None
    •Filtered Taste: Pure

Combi +/- $225 – Fact Sheet

  • •Filtration Quality: 0.2 Microns (bacteria, protozoa, cysts, algae, spores, sediments, and some viruses)
    •Filtration Volume: Ceramic 13,200gal / 50,000L, Charcoal 105gal / 400L
    •Filtration Media: Replaceable Ceramic / Replaceable Activated Charcoal
    •Filtration Flow: +/- 1 quart / liter per minute
    •Filtered Turbidity: None
    •Filtered Aroma: None
    •Filtered Taste: Pure

Expedition +/- $1200 – Fact Sheet

  • •Filtration Quality: 0.2 Microns (bacteria, protozoa, cysts, algae, spores, sediments, and some viruses)
    •Filtration Volume: 26,400gal / 100,000L
    •Filtration Media: Replaceable Ceramic
    •Filtration Flow: +/- 4 quarts / 4 liters per minute
    •Filtered Turbidity: None
    •Filtered Aroma: None
    •Filtered Taste: Pure

There are some variations here, but with the exception of volume and flow, the pocket and Combi filters are almost identical, the expedition is more of a camp filter, but I suppose you could pack it. The replacement filters (Pocket / Combi Cer – Car / Expedition) are fairly expensive, but the volume they’re capable of makes up for the cost if you plan to use the filter this much. These are really great products, but the initial cost will be prohibitive to people on tighter budgets.

Product Group 2A: Sawyer Point One Biological Filter Variations – Print Brochure

These filters are sold as a squeeze, gravity, and pump style with different adapters and configurations. The filters are Non replaceable sealed element hollow fiber membrane (kidney dialysis machine technology). But they’re guaranteed for 1 million gallons (I’m not sure that the guarantee will work for you post collapse though) and are touted as an indefinite use filter by the use of periodic back flushing and maintenance. If the filter ever does happen to break on you though, they’re very affordable and stocking up on them won’t be too difficult. Let’s delve in.

Point Zero Series $20 – $220 (average $50) – flow rate report – microbiological test report

  • •Filtration Quality: 0.1 Microns (absolute) (bacteria, protozoa, cysts, algae, spores, sediments, and some viruses)
    •Filtration Volume: Indefinite (yes indefinite with maintenance back flush and care)
    •Filtration Media: Non Replaceable Hollow Fiber Membrane
    •Filtration Flow: 4 quarts / 4 liters per minute Squeezed or up to 5 gallons per minute at max inlet 40psi
    •Filtered Turbidity: None
    •Filtered Aroma: None
    •Filtered Taste: Pure

These filters are excellent. They’re lightweight, easy to use, filter down to an extremely small micron size, and are extremely inexpensive and reliable. They do not have replaceable media, but they are considered indefinite use as long as you regularly back flush the filter with the included back flush syringe and prevent it from freezing with water inside. If you do happen to break it, they’re so affordable you can buy backups. These filters really only have 1 draw back in my opinion, and that is due to their hollow membrane pore construction they do not filter out and dissolved solids or solutions. That is to say that they cannot filter out anything that is completely dissolved into the water.

Product Group 2B: Sawyer Point Zero Two Biological Purifier Variations

These purifiers are sold as a squeeze, gravity, and pump style with different adapters and configurations. The purifiers are Non replaceable sealed element hollow fiber membrane (kidney dialysis machine tech). But they guaranteed for 1 million gallons and are touted as an indefinite use filter by the use of periodic back flushing and maintenance. If the filter ever does happen to break on you though, they are fairly affordable and stocking up on a small supply is doable.

Point Zero Two Series $140 – flow rate report – microbiological test report

  • •Purification Quality: 0.02 Microns (bacteria, protozoa, cysts, algae, spores, sediments, and all of the most common viruses CDC: Scroll all the way down)
    •Purification Volume: Indefinite (yes indefinite with maintenance back flush and care)
    •Purification Media: Non Replaceable Hollow Fiber Membrane
    •Purification Flow: 4 quarts / 4 liters per minute Squeezed or up to 5 gallons per minute at max inlet 40psi
    •Purification Turbidity: None
    •Purification Aroma: None
    •Purification Taste: Pure

If you haven’t noticed the above facts, these are actually not considered filters anymore, but purifiers. These purifiers are capable of removing every harmful thing (that is not in dissolution) from the water. Again, the only drawback is that due to the hollow fiber technology, these purifiers do NOT remove anything that is completely dissolved into the water. They pass everything that is smaller than .02 Microns in size without absorption.

Product Group 2A & 2B both function in exactly the same manner, but the Point Zero Two variation has smaller pore sizes. Both of them utilize an ABSOLUTE micron measurement which is much more stringent than the AVERAGE micron measurement. This basically means that absolutely NO particles, biology, or vectors of the specified micron size or larger will be found in the processed water.

The different variations of these products are the same core filter or purifier with different peripherals included in the package. For example, the SP129 package contains one Point One filter, one 1L collection pouch, and a mouthpiece valve for $45 while the SP131 contains one Point One filter, 3 collection pouches, a back flush syringe, and a mouthpiece valve for $45, and the SP181 All In One packages contains 1 Point One filter, 2 mouth piece valves, 1 faucet adapter hose, 1 back flush syringe, 1 1L collection pouch, and a bucket adapter kit for $60. Here’s a view of their water products.

At the end of the day, in my opinion the best investment would be to purchase both a Sawyer Zero Point Two purifier and the Katadyn Hiker Pro along with some extra filters for the Katy. The reasoning is that while some chemicals can slip by all but the most advanced filtration and purification techniques, a glass fiber / activated charcoal filter pump unit used as a post-filter would help to capture some chemicals by absorption while the Sawyer purifier will function to eliminate all of the smaller non dissolute “badies” such as HEV/HAV/SARS. The sawyer will benefit and accommodate the pressurization that the pump filter will add to the line and this will speed your collection up as the drop tube can be easily dropped into the water source, the pump outlet can be connected to the Sawyer very easily, and the Sawyer can be adapted to a hydration pack drink tube so you never really have to drop your kit to refill your bladder if you’re traveling with a buddy.

If you are trying to collect water in an environment that is potentially hostile you can just use the sawyer collection pouches to grab the water and take it with you to purify it in a safer environment. Just bear in mind that the Katy media would need replacement after about 200 gallons (you could probably get more since it’s used as a post filter). Most filters cannot remove toxic chemicals due to the dwell time required to absorb them onto the charcoal media. In fact, even distillation does not remove all chemicals because some exhibit the same properties of evaporation and boiling/condensation points. Choose your water source more wisely, and/or use the old fashioned method of digging a hole a few feet from your source water and collect from the water that has flowed into the hole. The Katy is mainly used as a pump, but the filter can help to improve taste that the Sawyer may not. You can refer to the CDC for further information on filtration properties and effectiveness here.

My personal configuration currently is a combination Katadyn Hiker Basic / Sawyer Point One filter connected in series so that the Sinker/Screen and Bobber are connected to the inlet of the Sawyer Point One filter, the Sawyer outlet is connected to the Hiker inlet, the Hiker outlet is connected to a quick disconnect Camelbak adapter and the QD connects to my Camelbak drinking tube after removing the bite valve.

Connected in this manner I am using the Katadyn prescreen and bobber to screen the water out going into the Sawyer. Since the Sawyer is back-flushable I use it to capture all sediment, bacteria, and protozoa prior to the Katadyn Glass Fiber / Charcoal unit to extend the life of the filter. I am using the Glass Fiber / Charcoal filter to absorb any dissolved contaminants that the Sawyer passes through which can help to improve any taste issues that the Sawyer may miss, and I’m using the pump unit to speed the process by pressurizing the line. An added benefit to using this system is that by slightly pressurizing my Camelbak’s bladder I can allow the filtered water to back flush the Sawyer filter automatically and lose only 1 liter of water from my 3 liter reservoir providing me with a freshly back flushed Sawyer filter and 2.5 liters of very clean water. Bear in mind that while this system is excellent for most water sources in the US, it does not filter our viral contaminations. I plan to upgrade the Sawyer Point One to a Point Zero Two purifier in the not too distant future. If viral contamination is a concern you can add 4 drops of unscented bleach per liter/quart or 12 drops to a full bladder directly into the drinking tube prior to connecting the filtration system and allow the bleach 10-15 minutes of contact time in the bladder before drinking.

Now, if you remember, I recommended saving your used Katadyn filter cartridges because they can be reused in a way. Allow your filter to thoroughly dry out by leaving it in the sun for a day or two. Take your used filter cartridge and turn it upside down to see a plastic circle in the center of the bottom plate. Using a 1/4″ or similar sized drill bit you can drill a hole through it. Now, just dump out any charcoal media that you may find inside. Now find a drill bit that just fits into the outlet hole in the top of the filter cartridge and drill down through the top to clear the silt barrier that holds the charcoal in. Now, run some tap water through the inlet hole of the filter to wash out any residual charcoal or drill shavings that may still be inside.

Now reinstall the filter into your pump and cycle about a quart of fresh tap water through the filter to remove any more filtration media or shavings that may have survived your first two attempts. You now have a cartridge that can turn your Katadyn filter into a basic hand pump to use on your Sawyer indefinitely. Warning: This is only recommended for filtration cartridges that have only ever been used as a post filter behind a Sawyer or other similar smaller micron filtration system.

If you’ve ever used a filter cartridge to directly filter contaminated water this is not recommended because bacteria and or cysts could be present on the dirty filtration media and could potentially make their way through the filter in the future. If you want to convert a used filter of this type be sure to allow the filter to soak in a water/bleach solution of at least 1% for 24 hours, then allow the filter to thoroughly dry out in direct sunlight.


Prizes for this round in our non fiction writing contest include…

  1. First place winner will receive – Two (2) Just In Case… Classic Assortment Survival Food Buckets courtesy of LPC Survival, a $150 gift certificate for Remington ammunition courtesy of LuckyGunner, aWonder Junior Deluxe grain mill courtesy of Kitchen Neads, a one year subscription to the Personal VPN service courtesy of unspyable and a Survival Puck courtesy of Innovation Industries, LLC.
  2. Second place winner will receive – One case of Future Essentials Canned Organic Green Costa Rican Monte Crisol Coffee courtesy of Campingsurvival.com and Solo Stove and Solo Pot Courtesy of EmergencyFoodWarehouse.com.
  3. Third place winner will receive – a copy of my book ”31 Days to Survival: A Complete Plan for Emergency Preparedness“ courtesy of TheSurvivalistBlog.net, a copy of “The Survival Medicine Handbook” courtesy of www.doomandbloom.net and a Wolf Pack Coffee Mug Jumbo Mug courtesy of Horton Design.

Be sure to read the rules before entering… This contest will end on January 15 2014

About M.D. Creekmore

M.D. Creekmore is the owner and editor of TheSurvivalistBlog.net. He is the author of four prepper related books and is regarded as one of the nations top survival and emergency preparedness experts. Read more about him here.


  1. As I do not control my normal water source (city water) I have 3 water filters. I have an AC, counter top unit that we filter our daily drinking water with. It’s back up is a Royal Berkey. I also have a Katadyn Vario for portable use. I also have a filter, non-powered, on my camp trailers inside faucet.

    Without water you will die. Without clean water you are only postponing the inevitable.

  2. Glad to see someone else promoting the Sawyer filter and purifier products. They have a very good product in use worldwide by missionaries. I was personally introduced to them just after the Haiti earthquakes and have spread the word about them ever since. We have the gravitational bucket kits as well as the squeeze bags for personal use, or to refill the hydration packs.

    Thanks for the other comparisons in your post.

  3. worrisome says:

    The two filters, used together, what is the approximate weight of carrying them both?

  4. I used the First Need filter on my several trips to India, never got sick. I was filtering tap water. It was pretty slow, ok for one person but it would be difficult for long term use. Perhaps the new ones are faster. Tap water would be insta-sick for a Westerner in India. Any water that wasn’t filtered or bottled at a factory should be regarded as poison by a Westerner.

  5. I carry in my backpack the Katadyn Pocket filter with a Sweetwater inline filter to help extend the life of the Katadyn; I use pieces of nylon stockings as a screen on the intake float as well, again to help extend the life by removing as much silt and larger ‘floaties’ before getting filtered.
    I also use my Steri-Pen with the solar recharger if I still question the water, which I always bring with me whenever I travel to other countries. I have never had any issues with tap water treated using the Steri-Pen whenever in Brasil, Argentina, India, Israel, or Hungary.

  6. My on the move system is an Aquamira frontier , a army 5qt . ” vietnam jungle ” collapsable canteen , israeli water purification tabs . I have a small bottle of citric acid ( gets rid of the iodine taste from the water purification tabs ) . I plan to use my army water bag size A to do the actual collection , then strain ( with coffee filter ) and treat in camp or in a more stable area , I will only use the frontier in an extreme emergency .

  7. very good info. about the filters and should really consider them because they will save your life.

  8. Great article David thanks for the info. I was wondering, if during your research, what system there is to filter the chemicals also. The reason I ask is because my wife just saw something online about fluoride and the alledged side effects, such as cancer, brain damage(causing stupidity), causing a person to be docile/controlable (sheeple), toothloss,and a couple other things. And has been done to us with intent, knowing the effects.
    Also w-mart sells gallon jugs of water with the picture of a baby,and says Nursery, that has fluoride added to it!!!

  9. Excellent article. I’ve seen a lot of people with survival kits didn’t contain any kind of water filtration. They did have their own purified water at home that they replaced regularly, but the main point of survival kits is to be ready for everything. And that includes their water stock being damaged or unusable.

  10. Very nice article, David. Thanks. It is nice to see the technical comparisons and price ranges.

    Is anyone familiar with the AquaPail water purifier? They come in different sizes, all too heavy for bug out bags. We have the 1000 gallon variety to supplement the Life Straw and Life Straw Family filters, and bleach. They claim to get EVERYTHING out of the water, and actively kill everything including virus. Amazon carries them, but with little feedback.

  11. Chuck Findlay says:

    I have several water filters, hands down the Katadyn Pocket filter is the best portable filter. And while it’s expensive to buy, it’s likely you will never need to buy a replacement element (as long as you don’t let a water-filled element freeze.) it filters 13,000 gallons of water, at a use rate of 1 gallon a day, every day it will filter water for 35-years. That easily makes it the least expensive water filter made when you factor in element replacement. My Katadyn Hiker is only good for 300 gallons and the replacement elements are $40.00

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