RapidPure Universal Purifier Bottle Adapter Review

Rapidpure Bottle Adapter Review 640

The RapidPure Universal Purifier Bottle Adapter is a portable water purifier that you can screw onto wide-mouth bottles from Nalgene, Camelbak, Hydro Flask, or Kleen Kanteen to turn them into water purifiers. It’s a great add-on to your existing bottle/hydration setup when you hike or travel to an area where it’s necessary to filter out viruses, bacteria, protozoa, chemicals, heavy metals, pesticides, and microplastics from backcountry or international water sources. To drink, you simply flip up the mouthpiece in the cap enclosure and suck. There’s no squeezing or pressing necessary to have a cold drink of purified water.

Specs at a Glance

  • Filter technology: Ultraceram electroabsorption, infused with silver and carbon
  • Virus Reduction 99.9999%
  • Cyst Reduction 99.9975%
  • Bacteria Reduction 99.9999%
  • Lifespan:
    • the first 25 gallons as a purifier effective against viruses, bacteria, protozoa, cysts, and giardia
    • an additional 220 gallons as a filter for bacteria, protozoa, cyst, and giardia removal (but not viruses)
  • Purification speed: 1.2L/minute
  • Third-party tested: Yes. Certified to exceed US EPA water purification standards.
  • Freeze resistant: Yes. 3rd party certified as water purifier after initial freeze/thaw cycle and as water filter after multiple freeze/thaw cycles.
  • Bottle compatibility: wide-mouth bottles from Nalgene, Camelbak, Hydro Flask, or Kleen Kanteen

RapidPure Universal Purifier Bottle Adapte

Treatment Capacity
Ease of Use

Convenient and Effective

Turn any wide-mouth bottle into a water purifier. This product is convenient and ingenious!

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The Universal Bottle Adapter has three components, a cap, straw, and the purifier element
The Universal Bottle Adapter has three components, a cap, straw, and the purifier element.

Water Purifier Adapter Assembly

The Rapidpure Water Purifier Adapter has the components: a screw-on top, the filter/purifier element, and a plastic straw that connects the two. The purifier element is designed to sit on the bottom of your bottle, so you can filter all of the water it contains.

Trim the length of the straw to fit your bottle
Trim the length of the straw to fit your bottle

Since bottle heights vary, you’ll have to trim the length of the plastic straw that links it to the screw-on cap, so that it can be twisted tightly shut. This is an easy process that requires a pair of scissors. For example, I had to trim about a quarter-inch off the straw so I could screw down the top lid on a 32 oz wide-mouth Nalgene bottle.

Attach the straw to the filter:purifier element and screw the cap back on
Attach the straw to the filter/purifier element and screw the cap back on

Push the end of the straw back onto the filter/purifier element, screw-on the top and you have a fully functioning bottle-based purification system.

Screw-On Top

The RapidPure comes with a screw-on top lid that is compatible with wide-mouth bottles, like the Hydro-Flask bottle shown here. The screw-on lid has a cap and a flip-up straw to drink from. The two prevent what’s known as cross-contamination, where you contaminate the drinking straw by touching it with hands that have been made wet from a contaminated water source.

The top lid is compatible with a wide range of wide-mouth bottles
The top lid is compatible with a wide range of wide-mouth bottles

The cap is not watertight so you can’t submerge it, but it works remarkably well at keeping dirty hands from touching the drinking mouthpiece. The mouthpiece has a plastic flange, that you can safely touch even with dirty hands, to flip it up for drinking or push back down into its recessed housing. This is my favorite part of this product because cross-contamination is a big problem with many other filter and purifier solutions unless you’re very careful.

When you’re ready to drink you can flip up the mouthpiece without touching and contaminating it.
When you’re ready to drink you can flip up the mouthpiece without touching and contaminating it.

When you’re ready to refill the bottle, you unscrew the lid, keeping the plastic top cap closed, and pull out the full assembly (cap, straw, and filter). Because the cap is closed, you can put it down on the ground without worrying about compromising the sipping straw. Refill the bottle with “dirty” water then replace the entire assembly, screwing the cap closed, so you can drink safely once again.

Filter/Purification Element

The purification element used in the RapidPure Universal Bottle Adapter pulls contaminants out of water based on their electrochemical charge instead of removing them using a mesh-like screen, which is how hollow tube filters, such as the Sawyer Squeeze or the Katadyn Befree, operate. This lets the RapidPure purification element remove viruses that hollow tube filters can’t remove by occlusion alone. It also makes the RapidPure purification element freeze proof, although its removal efficacy diminishes after multiple freeze/thaw cycles, so it only removes bacteria, protozoa, cyst, and giardia (equivalent to a filter) after it’s been re-thawed a second time. If you backpack or hike in cold weather, that’s still a pretty big benefit since freezing destroys  hollow tube water filters.

The RapidPure purification element is also infused with silver to kill all of the viruses and biological contaminants it removes so they can’t reproduce, in addition to carbon to help improve the taste of the water and remove unpleasant odors.

While electroabsorption as a water purification technology is fairly new, there are other popular water purification products that already use it including the very popular Grayl GeopressEpic Water Bottles, and Mizu Adventure Purifier Bottles.

Unfortunately, there’s no way to really keep track of how much water you’ve purified so you know when it’s switched from being an effective purifier capable of removing viruses to just a water filter. While the maximum capacity of each filter cartridges is specified at 200 gallons, the manufacturer recommends changing the filter every 100 liters or, once every 25 days of use, based on 1 gallon or 4 liters per day if you need to remove viruses. Otherwise, you can replace the filter cartridge when it becomes too difficult to suck water through it. This will depend to a great degree on the quality and murkiness of the water that you need to filter. Backflushing is not necessary or even possible.

Comparable Bottle-based Water Filters and Purifiers

Make / ModelTypeWeightCapacityReplaceable Filter/PurifierPrice
Mizu V12 Vacuum Water Purifier BottlePurifier15.4 oz40 gallonsNo$74
RapidPure Intrepid Water Purifier BottlePurifier9.2 oz25 gallonsyes$59
Lifestraw Flex Water Filter BottleFilter1.7 oz500 gallonsNo$35
Katadyn BeFree Water Filter BottleFilter2.3 oz250 gallonsYes$40
Lifestraw Go Water Filter BottleFilter7.8 oz264 gallonsYes$45


The RapidPure Universal Purifier Bottle Adapter is a great solution for adding a water filter/purifier to the wide-mouth water bottles you already own or for swapping it between bottles if you carry several at once. The difference between a water filter and a water purifier is that purifiers remove viruses, while filters don’t. While this is often unnecessary (in the United States) unless you travel internationally, there’s really no cost penalty to using the RapidPure Purifier Bottle Adapter for everyday or backcountry use when filtering is required.

While the RapidPure Bottle adapter reviewed here is convenient to use, I think its sweet spot is for day-hikes, fishing, cycling and recreational activities where water if fairly abundant. For longer trips or higher volume use, there are much more reliable, though heavier and more expensive solutions available. For example, MSR’s Guardian water purifier is one option I would recommend while a filter such as the Sawyer Squeeze Water Filter in combination with an Ultraviolet Katadyn Purifier to kill viruses would be another (see Ultraviolet Water Purification 101.)

Disclosure: RapidPure provided the author with a sample product for this review.

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  1. Please remind people to alcohol or disinfect their scissors before cutting off the tube!

    • While it is normally important to keep your “tool” clean, it doesn’t matter in this case because the end of the straw never comes in contact with the clean water stream.

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