I have treated water from glacial streams, muddy cattle ponds, and questionable trail seeps across the Triple Crown trails and the Te Araroa, and I have also paid the price for getting it wrong. I have had both Giardia and Cryptosporidium on trail, and neither is something you forget. After more than 30 years of backpacking and thru-hiking, and several years managing an outdoor retail store, I have come to rely on water purification tablets with a high-quality backup that I use in conjunction with either a Backpacking Water Filter, Gravity Water Filter, or a Water Bottle with a Filter.
This guide is for thru-hikers and backpackers who want a reliable, packable water treatment for the backcountry. My current top pick is the Katadyn Micropur MP1, with Aquatabs as the best value option for long thru-hikes. The main trade-off to understand is treatment time versus what the tablet actually kills, since the fastest tablets do not always protect against viruses.
Quick Picks – Best Water Purification Tablets
- Best Overall: Katadyn Micropur MP1 – chlorine dioxide that handles bacteria, viruses, Giardia and Cryptosporidium with not much real aftertaste; my default on most trips.
- Best for Thru-Hiking & Value: Aquatabs – cheap per tablet, up to 100 to a box, and fast in clean water; what you will see plenty of long-distance hikers carrying.
- Best Against Viruses: Potable Aqua Chlorine Dioxide – EPA-registered purifier, individually wrapped, strong on the full range of nasties when you are unsure of the source.
- Best Iodine Option: Potable Aqua Water + PA Plus – a proven iodine system with neutralising tablets to kill the taste; a solid backup, though not virus-rated on its own.
- Best Drops: Aquamira Water Treatment Drops – two-part chlorine dioxide drops, very light, treats up to 30 gallons; good for couples or longer carries.
How We Tested
The water purification tablets in this guide are researched and, where possible, field-tested by an experienced long-distance hiker and former outdoor store manager. Across thru-hikes, shoulder-season trips, and bike touring in remote areas, I judge water purification tablets on what they actually kill (bacteria, viruses, Giardia and Cryptosporidium), treatment time, taste, packability, shelf life, and value for serious backpacking. Some of the items were supplied by the manufacturer and some were purchased by the author for this review. For more on how we research and review gear, see the BikeHikeSafari Gear Review Policy.
Water Purification Tablets Comparison Table
| Brand | Pack Size | Active Ingredient | Treatment Time | Removal | Shelf Life |
|---|---|---|---|---|---|
| Katadyn Micropur MP1 Purification Tablets | 20 | Chlorine dioxide | 30 mins | Bacteria, Viruses, Giardia, Cryptosporidium | 5 years |
| Aquatabs Water Purification Tablets | 30, 50, 100 | Sodium dichloroisocyanurate | 30 mins | Bacteria, Viruses, Giardia, Cryptosporidium | 5 years |
| Potable Aqua Chlorine Dioxide | 30 | Chlorine dioxide | 4 hours | Bacteria, Viruses, Giardia, Cryptosporidium | 4 years |
| Potable Aqua Water + PA Plus | 50 | Iodine | 30 mins | Bacteria, Giardia, Cryptosporidium | 4 years |
| Aquamira Water Treatment Drops | 1 oz (treat 100L) | Chlorine dioxide | 15 mins | Bacteria, Viruses, Giardia, Cryptosporidium | 4 years |
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Best Water Purification Tablets and Drops 2026 – Detailed Reviews
Best Water Purification Tablets – Overall
Katadyn Micropur MP1 Purification Tablets
Active ingredient: Chlorine dioxide
Treatment time: 30 min (clear water) to 4 hours (cold/dirty)
Kills: Bacteria, viruses, Giardia, Cryptosporidium
Dose: 1 tablet per litre
Pack size: Box of 20 tablets
Shelf life: 5 years
Pros:
> Effective against bacteria & viruses
> Ready to use in 30
> Has a 5-year shelf life
Cons:
> So popular retailers sometimes run out of stock
> Can take 4 hours in dirty water
This is the tablet I reach for first. Chlorine dioxide covers the full range, including viruses and Cryptosporidium, which the cheaper iodine and basic chlorine options do not. The warmth-to-weight equivalent here is protection-per-gram, and the MP1 is hard to beat.
It suits everything from 3-season thru-hikes to questionable water sources where I am not sure what is upstream. If I could only carry one tablet, this would be it.
In real use it is genuinely no-fuss: one tablet per litre, shake, wait. I have been using this product for longer than I can remember and I find that I need to wait half an hour for clean-looking room-temperature water. If you are purifying dirty or cold water, the packaging recommends waiting four hours before drinking. It tastes ok, there is not too much aftertaste to complain about, and it tastes much better than iodine-based tablets. The only catch is it is so popular that retailers sometimes run out of stock.
Trade-off: Slower than Aquatabs in clean water, and pricier per tablet.
Best for: Backpackers and thru-hikers who want one tablet that covers everything, including viruses.
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Best Water Treatment Tablets – Runner Up
Aquatabs Water Purification Tablets
Active ingredient: Sodium dichloroisocyanurate, chlorine-based
Treatment time: 30 mins
Kills: Bacteria, viruses, Giardia, Cryptosporidium
Dose: 1 tablet per 2L
Pack size: 30,50 or 100 tablets per box
Shelf life: 5 years
Pros:
> It can kill 99.99% of microorganisms
> It’s really quick to work & tastes okay
> 30, 50 or 100 tabs per box
> It has a 5-year shelf life
Cons:
> It’s such a popular water purification tablet that retailers sometimes run out of stock
Aquatabs is the value workhorse. A global brand with over 25 years in business, supplying major aid and defence agencies worldwide, and the box comes in a choice of 30, 50 or 100 tablets to a box makes. This keeps the cost per litre very low, exactly what matters on a long thru-hike.
It suits long-distance hikes and resupply-heavy trips where you are treating water daily for months and want to keep costs and weight down.
In use it is quick and tastes okay. The main thing to watch is dose: one tablet purifies two litres of clean water in about 30 minutes, but if the water is dirty, one tablet is only enough for about three-quarters of a litre. On the Sierra section of the Pacific Crest Trail and other trails you will see many ultralight hikers using these.
Trade-off: Weaker against Cryptosporidium than chlorine dioxide; higher dose up for dirty water.
Best for: Thru-hikers and budget-focused backpackers treating clean-ish water in volume.
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Best Virus Treatment Tablets
Potable Aqua Chlorine Dioxide
Active ingredient: Chlorine dioxide
Treatment time: Up to 4 hours
Kills: Bacteria, viruses, Giardia, Cryptosporidium
Pack size: 30 tablets per box
Dose: 1 tablet per litre
Shelf Life: 4 years
Pros:
> Effective against bacteria & viruses
> Effective against Giardia and Cryptosporidium
> EPA registered as a microbiological water purifier
> 2.6 times the oxidizing capacity of chlorine
Cons:
> It requires up to 4 hours for the best results
This is a strong choice when you want full virus and Cryptosporidium coverage in a tablet. EPA-registered as a purifier with roughly 2.6 times the oxidising capacity of chlorine, it does not cut corners on what it kills.
It suits trips where the water source is genuinely sketchy such as standing water, livestock areas, or anywhere viruses are a real concern.
In use, the individually wrapped tablets take up minimal space in a pack or pocket and keep moisture out until you need them. The honest downside is patience: it can want up to four hours for the best results in poor water.
Trade-off: Slow when the water is cold or dirty.
Best for: Backpackers who prioritise full-spectrum protection over speed.
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Best Iodine Water Treatment Tablets
Potable Aqua Water + PA Plus
Active ingredient: Iodine (plus PA Plus neutralising tablets)
Treatment time: 30 min iodine
Kills: Bacteria, Giardia; not effective against viruses
Pack size: Two bottles, 50 tablets each; 25 treatments per box
Shelf life: 4 years advertised
Pros:
> Effective against bacteria & Giardia
> PA Plus tablets to neutralize the taste
> Water is ready to drink in half an hour
Cons:
> Not effective against viruses
This is the classic iodine system, and it still earns a place as a proven, reliable backup. The PA Plus tablets are the clever part, they neutralise the strong iodine taste that puts a lot of people off.
It suits shorter trips and emergency kits where you want something cheap and dependable, and where viruses are not your main worry.
In use, the process is a bit more involved: add two iodine tablets to a litre, shake, wait five minutes, leave it 30 minutes, then add two PA Plus tablets, shake, and wait three minutes. I don’t fancy the taste of a tablet, which can be a little chalky, but the PA Plus genuinely helps.
Trade-off: Not virus-rated, two-step process, iodine not ideal for long-term or for some health conditions.
Best for: A budget backup or short-trip option where viruses are not a concern.
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Best Water Treatment Drops
Aquamira Water Treatment Drops
Active ingredient: Chlorine dioxide (two-part drops, Part A + Part B)
Treatment time: As little as 15 min
Kills: Bacteria, viruses, Giardia, Cryptosporidium
Capacity: Treats up to 30 gallons
Shelf Life:
Pros:
> Effective against bacteria and viruses
> Effective against giardia & cryptosporidium
> Purifies water in as little as 15 mins
> Treats up to 30 gallons of water
> It’s made in the USA
Cons:
> It’s such a popular water purification treatment that retailers sometimes run out of stock
Aquamira is the pick when you want drops rather than tablets. Two-part chlorine dioxide, very light, and it treats up to 30 gallons from a small kit, strong value over a long trip or for a pair of hikers.
It suits longer carries and couples, where the per-litre cost and weight of drops beats individually dosed tablets.
In use you mix seven drops from each bottle, wait five minutes for them to react, add to a litre, shake, and let it stand 15 minutes or more. It is fast for chlorine dioxide and the long shelf life means you can keep using it well after the manufacture date.
Trade-off: The two-bottle mixing step is fiddlier than dropping in a single tablet.
Best for: Backpackers who want light, high-capacity treatment and don’t mind a mixing step.
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Water Purification Tablets Buyers Guide
Water Purification Tablets Buyers Guide
Tablets vs Drops vs Filters
Tablets and drops win on weight and packability, they take up almost no space, which matters when every gram and litre of pack volume counts.
Backpacking Water Filters are the most popular trail choice but can clog in dirty water.
A water bottle with a built-in filter is fine for travel but not my favourite for backpacking.
I carry tablets as a lightweight backup for when a filter clogs, freezes, or fails.
Protection: Bacteria, Viruses & Protozoa
The whole point is protection against the diseases you catch from dirty water — bacteria, viruses, and protozoa like Giardia and Cryptosporidium. I have had both Giardia and Cryptosporidium on trail, they are common and account for more than 80% of water borne illness, and I could have prevented them by treating my water. If in doubt, treat it.
Not every tablet covers everything: chlorine dioxide (Katadyn Micropur, Potable Aqua CD, Aquamira) covers viruses and Cryptosporidium; basic iodine and some chlorine tablets do not.
Water Purification Time
Most tablets need about 30 minutes in clear, room-temperature water. Cold or dirty water can push chlorine dioxide tablets out to four hours. If you are often thirsty on arrival at camp, treat a spare litre early.
Taste
Taste matters more than people admit, especially if you are coaxing a tired hiker or a child to keep drinking. Iodine is the worst offender; chlorine dioxide tablets like the Micropur are close to tasteless. PA Plus neutralising tablets exist specifically to fix iodine taste.
Shelf Life
Most tablets last around five years. I have used them well beyond their used-by date with no problem, but do your best to carry in-date tablets into the backcountry. Keep an eye on this if they live in a long-term emergency kit.
Fill / Dosing for Dirty Water
Dose is not fixed: dirty water often needs more tablets per litre, or a flocculant like Chlor-Floc to drop the sediment first. Read the packaging rather than assuming one tablet per litre always applies.
Value for Money
I deliberately don’t quote prices since they change, check the current price via the links. Cheaper is not automatically better value; safety comes first. Buying larger packs usually lowers the cost per tablet, which is why Aquatabs works out so well for long thru-hikes.
Conclusion
Overall, the Best Water Treatment Tablets are:
- Best Overall: Katadyn Micropur MP1
- Best for Thru-Hiking & Value: Aquatabs
- Best Against Viruses: Potable Aqua Chlorine Dioxide
- Best Iodine Option: Potable Aqua Water + PA Plus
- Best Drops: Aquamira Water Treatment Drops
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Frequently Asked Questions
What is the best water purification tablet for backpacking?
For most backpacking, the Katadyn Micropur MP1 is my top pick — chlorine dioxide that covers bacteria, viruses, Giardia and Cryptosporidium with almost no taste. For long thru-hikes on a budget, Aquatabs are hard to beat on cost per litre.
What is the best chemical to purify water?
Chlorine dioxide is the most effective for backpackers because it protects against the widest range, including viruses and Cryptosporidium. Plain chlorine (NaDCC) is next best and cheaper, with iodine as a backup that struggles against Cryptosporidium and tastes worse.
Do water purification tablets kill Giardia and Cryptosporidium?
Chlorine dioxide tablets (Micropur, Potable Aqua CD, Aquamira) kill both, though Cryptosporidium needs the longer contact time. Iodine and basic chlorine tablets handle Giardia far better than Cryptosporidium, so check the label before relying on them.
How long do water purification tablets take to work?
Most need about 30 minutes in clear, room-temperature water. Cold or dirty water can extend chlorine dioxide tablets to up to four hours, so treat early when conditions are poor.
Are water purification tablets worth it?
Yes, every hiker and backpacker should carry some form of treatment. Filters clog, freeze, or break, and tablets are a near-weightless backup that can make questionable water safe to drink. Having had Giardia and Cryptosporidium myself, I would not head into the backcountry without a backup.
How do you treat dirty or silty water with tablets?
Increase the dose per litre and extend the wait time, or use a flocculant such as Chlor-Floc to clump and settle the sediment before pouring off the clearer water on top. Pre-filtering through a bandana also helps.
Does boiling water remove chlorine?
Yes, boiling for several minutes drives off chlorine and can improve taste if your treated water still tastes strongly of it.
BikeHikeSafari Gear Review Process
The author, Brad McCartney from BikeHikeSafari is a small independent adventurer and outdoor gear tester who owns and runs BikeHikeSafari.com.
BikeHikeSafari is not part of a large blog network and is proudly independent. All reviews on this site are independent and honest gear reviews of outdoor products by the author.
The author, Brad McCartney is a very experienced triple crown thru-hiker, adventurer, and bike tourer having spent 1000s of nights sleeping in a tent and sleeping bag (Read more). He was a manager of an outdoor retail store and is very experienced in what is important when using and testing gear for reviews like this.
BikeHikeSafari will never receive any money for reviews and they do not accept sponsored reviews on this website. All the comments about the gear reviews are from the author based on his years of experience. Hope this independent review was helpful for you.
