LifeStraw Flex with gravity bag

Compact, lightweight water filtration system with expanded protection and 1 gallon gravity bag


LifeStraw Flex with gravity bag

NEW! LifeStraw Flex with Gravity Bag Multi-Function Water Filter - Removes Lead, Bacteria, Parasites and Chemicals is rated 4.9 out of 5 by 39.


Compact, lightweight water filtration system with expanded protection and 1 gallon gravity bag

    • Next level protection against heavy metals including lead as well as bacteria, parasites, microplastics, and organic chemical matter like pesticides, and herbicides
    • Versatile water filter can also be used in 4 ways.
    • Ultralight with high throughput, weighs only 6.94 oz (0.43 lbs), and capable of filtering 1 liter every 2 mins
    • This product gives back: one product, one school child, one year of clean water

Need Replacements?
Click Here

Your purchase has
an impact.

Shop Now

Next Level Protection

The LifeStraw Flex’s cutting-edge filter can handle a wide array of contaminants found in water across the globe.

Let Gravity Do the Work

The included gravity bag takes the work out of water filtration.

Perfect Addition to Your Survival Kit

There are no batteries to replace, no moving parts to wear out, and LifeStraw products do not expire.

  • How it Works
  • Specs
  • Data & Evidence

How it Works

How It Works

Maximize protection and water throughput with this ultralight, compact gravity filtration system. LifeStraw Flex is built to provide safe drinking water in almost any environment. The 2-stage filter offers next level protection against bacteria, parasites, and microplastics while also expanding protection against lead and some chemicals. It can be used with the included gravity bag, as a straw, attached to a hydration pack, or with a plastic water bottle.

Stage 1: The hollow fiber membrane removes

• 99.999999% of bacteria (E. coli)

• 99.999% of parasites (Giardia, Cryptosporidium, etc.)

• 99.999% of microplastics

Stage 2: The activated carbon capsule reduces

• Lead and other heavy metals

• Chlorine

• Bad odor and taste

• Organic chemical matter





  • Kit Includes: LifeStraw Flex filter, 1 gallon gravity bag, hose, backwashing syringe for cleaning
  • Filtration technology: Hollow fiber microfiltration membrane (0.2 microns) paired with a carbon fiber filter
  • Microbiological filter capacity: 500 gallons (2,000 liters). Pores clog over time as the filter is used; reaching end of life when water cannot pass through.
  • Carbon filter capacity: 25 gallons (100 liters). With frequent use, recommended to change fitler every 3 months.
  • Filter Size: 6.24 x 1.5 in
  • Gravity Bag Volume: 1 gallon / 3.7 liters
  • Hose length: 27.56 in
  • Gravity bag material: TPU laminated with 210 denier nylon fabric
  • Total product Weight: 6.94 oz (0.43 lbs)
  • BPA free
  • Recyclable
  • Replaceable carbon filter available


Lab Information

We believe that responsible manufacturing includes creating and maintaining a strong evidence base for our product claims and their intended impacts. All products undergo rigorous independent testing to meet or exceed protocols established by the US Environmental Protection Agency (EPA) and National Sanitation Foundation (NSF) We also built and run an ISO accredited water laboratory based in Vietnam that does quality validation and testing of all of our new and existing products.

  • Hollow fiber membrane filter: 0.2 micron pore size. Removes 99.999999% of bacteria, 99.999% of parasites, and 99.999% of microplastics.
  • Also removes turbidity (silt, sand, and cloudiness).
  • Carbon fiber filter: Improves taste while reducing lead and other heavy metals, chlorine, and organic chemical matter such as pesticides, herbicides, and VOCs.
  • Meets US EPA drinking water standards for bacteria and protozoa reduction.
  • Meets NSF/ANSI Standard 42 for chlorine reduction, bad taste, odor.
  • Meets NSF/ANSI Standard 53 for lead reduction
  • Hollow fiber filter lifetime: 500 gallons (2,000 liters)
  • Carbon filter lifetime: 25 gallons (100 liters)
  • Filtration powered by: suction (as a straw or in-line), gravity (when paired with a gravity bag) and pressure (when used with a plastic bottle).
  • Flow rate: 0.5 liters/min
  • EPA Est. No. 95395-KOR-1
  • WARNING: Cancer and reproductive harm. Learn more


Rated 5 out of 5 by from Life Saver I really wanted to test this product out in the woods. A weekend trip into the wild gave the me the opportunity to try the LifeStraw in all modes. As a purifying straw it fit on several different water bottle brands. As gravity Bag, it held water with no leaks and provided a steady flow of water. And in a moment of bravery, because you have to a good reviewer, I tried water from a clean flowing source. Seeing as how I yet to have been crippled by parasites and bacteria I have to give the LifeStraw a 5+ star rating. My brother who is an advid outdoorsman has been eyeballing the blue beauty since I opened the box. Maybe I'll let him use it on his next hunting trip.
Date published: 2018-11-09
Rated 5 out of 5 by from A load of my mind and back. I see the LifeStraw Flex with gravity bag as a valuable tool to have during emergency situations, travel or camping. It's such a small and lightweight design that easily packs away. Knowing you have up to 500 gallons of clean water (If you bring extra carbon filters) in your bag is a load off your mind and back. The 1-gallon bag is waterproof with a roll-top clip closure, strap to suspend the bag in the air. The bags nozzle locks in the tube to connect to the straw. It seems sturdy and protected and I see no reason it wouldn't double as a great dry bag.
Date published: 2018-10-28
Rated 5 out of 5 by from Good to have for a go bag I received this free as a sample. I know that lifestraw is a good brand for water filtration of any sort of water. This item here with the bag to help filter more water and to make it easier to fill bottles is a good idea. I find that the bag it self needs a seperate clamp form the one that u fold down and clamp as the bag does open a bit. There are also no extra filters with this and i think that there should be at least 1 extra filter as 1 of the filters only lasts for 25 gallons. The instructions could be a bit more simple. As to whether this filters water i find that it does as it says it does.
Date published: 2018-10-23
Rated 5 out of 5 by from The lifestraw is a lifesaver I'm so excited to he giving LifeStraw a multi-use water filter gravity bag a try. It performed wonderfully used it with river water and it filtered wonderfully the water tasted very clean and clear. It works great for a family with a one gallon capacity. #freesample
Date published: 2018-10-19
Rated 5 out of 5 by from Multi-use and gives back! The LifeStraw Flex with Gravity Bag Multi-Function Water Filter is such a great idea for Camping, traveling, or personal use. I'm very impressed that this product gives back by providing safe drinking water for a cold in need with each purchase. The LifeStraw itself was easy to assemble and take apart, attatches to water bottles, the gallon water bag provided and reduces lead and removes bacteria and parasites. Great to keep in the car too!
Date published: 2018-11-07
Rated 5 out of 5 by from Great To Have This is a really cool product, and a really great one to have around. I like that it is versatile and packable. The LifeStraw part can be used by itself as a straw or attached to the gravity bag. It is lightweight and fits easily into a bag. Now that I have it, I wouldn't go camping without it. It can make terrible water taste great. You don't have to worry about getting sick from the water if you have this. I think that everyone should keep these around. They're perfect for an emergency kit. You never know where you'll end up. but one thing I know is that you will always need clean water to survive. This product is invaluable for that. I'd especially recommend it to campers and travelers, but I'd really recommend it to anyone. It's great!
Date published: 2018-10-23
Rated 4 out of 5 by from Great for camping I just received this water bag just before a hunting. It works great. It holds a gallon of water and you can put a filter on it to filter out bacteria. This is a great tool for camping,Hiking or to put in a emergency bag. I would recommend this bag for any outdoodsmen.
Date published: 2018-10-26
Rated 5 out of 5 by from Amazing water filter! I received this product in a very timely manner. It has a 1 gallon bag that you can put any water in and the gravity of the bag filters the water down the straw. It is very convenient and very easy to use. You can bring it camping or out on a hike and not have to worry about water because you can grab any water available and know it’s safe to drink because of the filter system. We brought it camping and used water from the campground and it tasted amazing. We are very happy with the bag and filter.
Date published: 2018-10-24
  • y_2018, m_11, d_25, h_17
  • bvseo_bulk, prod_bvrr, vn_bulk_2.0.9
  • cp_1, bvpage1
  • co_hasreviews, tv_0, tr_39
  • loc_en_US, sid_1500308177007, prod, sort_[SortEntry(order=RELEVANCE, direction=DESCENDING)]
  • clientName_lifestraw
  • bvseo_shopify, bvseo-0.0.1

For this product LifeStraw flex gravity bag mulit-function water filter, how can you be sure it is time to replace the filter for this filter bag that carries a gallon at a time? Since it can filter 500 gallons is there a indicator of some sort?

Asked by: JudyCee
  • y_2018, m_11, d_25, h_17CST
  • bvseo_bulk, prod_bvqa, vn_bulk_2.0.9
  • cp_1, bvpage1
  • co_hasquestions, tq_1
  • loc_en_US, sid_1500308177007, prod, sort_[SortEntry(order=LAST_APPROVED_ANSWER_SUBMISSION_TIME, direction=DESCENDING)]
  • clientName_lifestraw