







Price: $399.95 - $63.99
(as of Nov 22, 2025 07:55:53 UTC – Details)
Military-grade water purifier pump removes viruses, bacteria, protozoa, and particulate from contaminated water sources virtually anywhere on earth
Meets NSF protocol P248 testing standard of the U.S. military, using medical-grade fibers to provide protection from the tiniest waterborne threats
Pumps at a rapid 2.5 liters per minute, treats up to 10,000 liters of water, and withstands freezing, drops, heavy use, and harsh environments
Purifier pump self-cleans on every stroke, providing consistently fast flow rates with zero hassle—no backflushing or filter-scrubbing ever required
Storage bag utilizes a PFAS-free DWR coating that is better for the environment and still keeps your gear dry
Pump measures 8.2 x 4.7 inches, weighs 17.3 ounces.; storage bag included; manufacturer’s limited 3-year warranty; made in the USA
10 reviews for MSR Guardian Water Purifier for Backcountry Use, Global Travel, and Emergency Preparedness
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$63.99

Why do you care –
Great product, i have been testing it out over …
Great product, i have been testing it out over the last few days and the result is always the same, good tasting clean water no matter the water source and FAST. I read many reviews on water filters before purchasing one and this one was at the top of most list’s and noted its down side was the size of the device upon receiving the guardian i would have to disagree the size is comparable to most systems and simple as could be for use. I will be taking it into the field on Friday for a week long backpack trip and after that i will comment more about the durability of the unit. As of now i am pleased with the quality it seams well built and easy to maintain and can be taken apart and serviced in no time if need be. It also came with a nice zip up carry case. I would say its well worth the money and will probably last me forever.Returned home from the trip, after a good field test I would go with 4.5 starts but will leave it a five. Wear the pump handle attaches to the plunger is a mixture of steel and plastic parts it held up fine but it is all held together with a plastic C clip, if you get much more than a moderate pump pace the clip hangs up and pops loud, I am certain this clip will fail and break at some point so i plan on finding a spare. The clip is basic something you would find at a auto parts store for cents and will be metal 🙂 the other thing i noticed in the promotion video for the pump it says as long as the filter on the end is wet it it will pump only water and no air….that is mostly true but on 2 occasions it pulled air and we were forced to hold it under water and it primed up and was fine. Other then the clip it pumps and cleans water very fast and efficient its quiet and easy to set up and put away i would buy it again.
Sean E. Bowen –
Comes in a nice zip up case with a fine mesh screen on …
I picked this up to have access to clean water for a group while backpacking/traveling or for emergency conditions where public water is contaminated. Think of boil water advisories when the local water main has broken. Remember this is a mechanical filter and that chemical or radiological contaminants are NOT removed by mechanical filters. This won’t help you fix the water in Flint, MI or magically turn seawater into potable water.Eager to see how this works, I ran a little test with a water source I know is contaminated with coliform bateria. I took samples from the source and from the water filtered by this unit. Running the samples and a control through a test kit showed the filtered water was indeed bacteria free.Ultralight backpackers will balk at the weight but for me I appreciate the ease of use. I was surprised a how fast the filtered water comes out. Fits my Nalgene bottle perfectly. I don’t have to mess with bags or wait around for gravity to work. Hose is long enough so you don’t fall in the pond or river trying to scoop up water.Comes in a nice zip up case with a fine mesh screen on top so when you put it away the hose can dry off with out contaminating the rest of your stuff. Be sure to buy the annual maintenance kit which is sold separately – it contains o rings and other goodies to maintain your pumpI like that this filters viruses. I wish I had had this on recent trips to India and the DR. Now I am better prepared! I also appreciate the fact that it backflushes itself on every stroke. Very clever.This thing is pretty expensive but it is so easy to use I am glad to have it.
Gary –
Great purchase
We do not like to carry extra drinking water with us in our small camper. This is perfect to filter the water from the campground. The water tastes good and it is quick and easy to use.
Adam –
DON’T get Giardia. DO get this filter.
AWESOME. Has been the sole source of water on 3 backcountry trips through the Boundary Waters for 4-6 thirsty guys and nobody has ever gotten sick. One campsite was situated ON TOP OF A BEAVER DEN, where the beavers angrily circled me as I pumped water from their stick munching spot, and still nobody got Giardia. Speaking of which, have you ever had Giardiasis? It’s not great. I once ate nasty snow in the North Cascades because I did a poor job of managing water, and 2 weeks later I had to time the 30 minutes between trips to the toilet to rush down to the pharmacy for Flagyl. DON’T GET GIARDIA. DO GET THIS WATER FILTER.
Todd M. –
Love this purifier
This MSR Guardian is not the smallest or lightest purifier, but it does a great job at what it is supposed to do. It takes a short amount of time to pump the purified water in a bottle. Even better is if your bottle or container has a wide mouth that can be screwed on to the device. Otherwise, you play a balancing act pumping and holding the container for the water so that is will not spill out.Doesn’t need a deep water source to be able to pump. Really like how it backflushes to keep it clean. You do want to make sure you keep this maintained over the years, especially if you do not use it all the time. It will keep some water in the device and you do not want it to dry out. There is a maintenance kit available to keep other working parts moving smoothly.It is very pricy, but it does a great job. It really makes the water taste great, and you have the peace of mind that you are getting clean water. While it is heavy for backpacking, I think the weight is worth it. I am very happy with it.
ThoTir –
Hochwertiger Wasserfilter, leichte Bauweise, praktische Tasche und für unsere Outdoor-Aktivitäten unerlässlich…..so können wir sicherer sein, beim Wassertrinken nicht krank zu werden … funktioniert tadellos
@REMI –
やや大柄な製品ですが浄水性能及び能力は一般の民間人が購入出来る携帯型浄水器としてはおそらく「No.1性能」でしょう。———————————————現在、各社より携帯型浄水器が販売されていますが皆さま騙されてはいけません。おそらく民間で販売されているモノの中ではこの製品以外全て「その場しのぎ」製品なので購入の際は良く性質をご理解の上、購入するよう本当に注意が必要です。こちらの本製品はアメリカ陸軍の要請により開発委託され採用されただけでなく一般にも市販されているかなり真面目な製品です。製品を使う毎にセルフクリーニングされ製品の状態をキープし続けるというかなり画期的な携帯型浄水器だと思いますがその他の製品は何かしらの濾過フィルターを搭載する事で浄水する構造なんです。そもそも濾過フィルターというのは一度使えば基本的に交換が必要です!例え短期の利用であったとしてもフィルター内には様々なバクテリアや不純物がフィルター内に残留しているので例え「1日しか使っていない!」場合でも10日間ほど放置してすればさてフィルター内はどうなっているのか冷静に考えてみて下さいませ。。。幾つかの例をあげるなら。。。(1)掃除機のゴミパック(2)家庭用カートリッジフィルター式浄水器(1)の場合1度の掃除で毎回ゴミパックを交換するご家庭は稀だと思いますが新品の内は何もございませんが何度かお掃除で使う内に掃除機の排気が何とも言えない排気臭に見舞われますよね?同じような事がフィルター式簡易浄水器でも起こると考えた方がいいでしょう。。。(2)ついてはメーカーの取扱い説明書にも必ず注意記載があるはずなんですが約1週間、ご利用が無かった場合にはカートリッジ及びフィルター内の水分の腐敗やバクテリアの増殖の可能性もありますので利用を停止し新しいカートリッジと交換を推奨。だいたいこんな感じの記載が必ずございます。フィルター内が一体どういう事になっているか等はわざわざ説明する必要もないですよね。。。アウトドアが一番楽しいシーズンはやはり夏です。しかしその夏こそが安価な携帯型浄水器製品にとって実はかなり宜しくない季節だったりします。。。高温と多湿で携帯型浄水器の使用環境としては最悪としかいいようがないのです。。。繰り返しで申し訳ないのですが1回もしくは1シーズン使えば「破棄」の確率も高くなりしかも交換用フィルターはどのメーカーも高いので結果的にコスパも高くなりがちです。これはアウトドアメーカーにとってはかなり「不都合な真実」なんですが販売する上での表記は食品類とは違いまして表記義務が実はメーカーには無い為にこのような事態になっているとお考え下さいませ。 「災害や事故に遭遇した時の為に。。。」 「万が一の時の為に。。。」などと本気でお考えになるのであれば東京都水道局の発表によれば平均的なご家庭で1日に使う水の量は「約214L」らしいのでフィルター式簡易浄水器ではおそらく機能面及び浄水能力ともにその役割を成しませんのでご注意下さいませ。安物買いの銭失いになるくらいなら「本製品」を選ぶ事を強くオススメ致します。ちなみにこの本製品以上の浄水能力のお求めの方一般市民レベルでは直接購入は出来ないはずなので現状ではこの製品がベストだと思って下さいませ。さすがにこの価格では買えないと仰る方へ。。。世の中には粉末タイプと錠剤タイプの「浄水タブレット」という製品がございます。。。(Aquatabs、WATABなど)(携帯型浄水器類と比べ即効性が若干劣ります)その手の製品なら必要な時に必要な分だけのご利用が可能なのでコスパも良いかと思います。濾過フィルター型の携帯型浄水器を検討される場合是非ともあわせてご検討下さいませ。
onifade –
ho scritto alla casa produttrice e non si sono degnati di rispondere – Fatte varie misurazioni sull’acqua e non filtra nulla, anzi, alcuni valori peggiorano e vorrei capire perchè! :-(( delusa e basita!
ΛLPΛSΞ –
Conforme à mes attentes
JORGE GARCÍA MONSALVE –
Muy útil