Choosing the Best Water Purification Tablets – Everything You Need to Know!

Categories: Outdoor Survival


Why are water purification tablets so important?

Everyone needs clean drinking water to survive, and easy access to it is something that every person should be entitled to. Unfortunately, that may not always be possible!

Most of us are lucky enough to have clean drinking water pumped directly to our homes and can, with a simple turn of a tap, help ourselves to copious amounts of this vital liquid, but what if something happened that made the water supply turn bad, or worse still, it was cut off completely?

Best Water Purification Tablets

Or….What if you’re away from home and there is no clean drinking water available? Maybe you’re on a hiking trip, you’ve lost your water bottle, and you’ve gotten lost. Maybe you’ve broken down in your car, in the middle of nowhere, miles from the nearest town and you have no water stashed in your trunk.

The point is, how can you guarantee the water you use or find, presuming you can find water, is safe to drink?

Whether you are traveling overseas or planning for an emergency situation, it is so important to know how to make water drinkable or potable.

There are a number of ways you can purify water and they’re all covered in a previous article of ours which you can read here – ‘How to Purify Water – Making Water Safe to Drink’, but this specific post is only going to deal with the most convenient of these methods, water purification tablets.

We’re going to tell you about our assessment of the best water purification tablets currently available based upon their shelf life, purification processing time, and effectiveness in eliminating pathogens, all of which are extremely important factors.

We will also be covering the benefits of using water purification tablets, the chemicals used in their composition, their practical uses, and a little back history about their development.

We hope you’ll find this post extremely useful, especially if you’re still deciding exactly what it is that you need. We’ll start with our list of the best purification tablets.

Five Best Water Purification Tablets

Katadyn Micropur MP1 Purification TabletsKatadyn Micropur MP1 Purification Tablets

  • 1 tablet treats a quart of water (1 liter)
  • 1 package contains 20 tablets
  • They have a shelf life of 5 years
  • Cryptosporidium clear in 4 hours
  • Giardia clear in 30 minutes
  • Virus and bacteria clear in 15 minutes
  • Chlorine dioxide formulated tablet


The American company called Katadyn is renowned for producing quality water filters.
As well as water filters they produce an excellent purification tablet that is chlorine dioxide-based.

Katadyn’s well earned reputation for producing quality outdoor goods has certainly helped in making MICROPUR purification tablets extremely popular with backpackers, campers, and preppers.

One thing that a large majority of user reviews highlight, as well as the manufacturer themselves, as being a huge positive, is that these tablets lack the bad taste that often remains in the mouth after drinking treated water. As is the case with most other chorine and iodine-based tablets.

With a wait time of 15-minutes for viruses and bacteria; and 30 for Giardia, Micropur tablets perform better, if only slightly, than many of the other options listed here.

Microspur will eliminate Cryptosporidium, but because this microscopic critter is quite tough to break down the statutory four hours will be needed for the water to be completely purified, which is the same as most treatments take.

A pack of 20 tablets can purify about 5 gallons of water (20 liters) each tablet purifying a quarter of a gallon (1 liter).

With its lightweight container and a shelf life of five years, these water purification tablets are certainly favorites of ours, and are well worth considering.

Aquamira Water Purifier Tablets - 50 packAquamira Water Purifier Tablets (Pack of 50)

  • 20 tablets treat a total of 5 gallons (20 liters)
  • Shelf life of 5 years
  • Wait time of 4-hours for cryptosporidium
  • Wait time of 30-minutes for giardia, bacteria, and viruses
  • Chlorine Dioxide-based


These tablets, which are chlorine-based, adhere to regulation standards of the Environmental Protection Agency and are regular water purification option for emergency groups and backpackers.

The tablets come with a half-hour wait period for viruses and bacteria, and take the statutory 4 hours to break down and eliminate Cryptosporidium.

One tablet will treat and purify a quarter of a gallon of water and there are. 20 tablets in each lightweight package.

The tablets come with a 5-year shelf life and are sealed in foil.

Potable Aqua Water Purification TreatmentPotable Aqua Water Purification Treatment

  • Bottle weight of 1.4 ounces
  • Bottle diameter is 3” high by 1” wide
  • Cold temperatures do not affect it
  • 25 water quarts can be treated with a 50-tablet container
  • Ineffective against cryptosporidium
  • Effective against Giardia, viruses, and bacteria
  • Shelf life of 1-year when opened and 4-years if unopened
  • Wait time of 35-minutes
  • Iodine-based


These tablets, which are iodine-based, are registered with the Environmental Protection Agency, and are frequently used by emergency organizations and military groups all over the world.

Every tablet contains a TGHP compound (Tetraglycine Hydroperiodide) of 20 mg, and upon immersion in water will release 8 mg of germinal iodine.

Due to its brief wait time of 35-minutes and its effectiveness in combating giardia, these iodine tablets tend to be used by humanitarian groups, hikers, campers, and people traveling to areas where water quality and cleanliness is generally poor.

To use them, add a couple of tablets to a liter or quart of water, slightly close the container, wait for about five minutes, shake the container, tighten it, then wait another 35 minutes.

To ensure maximum effectivness against giardia, refrain from opening the container before the 35-minute wait mark.

Aquatabs AQT100 Water Purification TabletsAquatabs AQT100 Water Purification Tablets

  • 50 gallons of water can be treated with100 tablets
  • Ineffective against cryptosporidium
  • Effective against Giardia, viruses, and bacteria
  • Shelf life of 5-years
  • Wait time of half an hour
  • Chlorine-based


Emergency groups like NATO and NGO have been successfully using these tablets for more than two decades, and it has been estimated that they have been used to treat over 3 billion gallons each year. With this past record they are considered to be the most dependable water purifying tablets in the world.

These chlorine-based tablets are effective in eliminating Giardia, bacteria, and viruses in 30 minutes, making them an excellent choice for use in the outdoors and for emergency situations.

The effervescent tablets quickly dissolve when dropped into water, and for a chlorine based tablet they leave very little if any unwelcome tastes in your mouth once the purification process has run its course.

Most of these tablets come in packs of 100 and can treat as much as 50 gallons of water in total!

Each package is divided further into individual strip of 10 tablets, which is ideal if you want to travel light as a strip can be slipped into a shirt or trouser pocket without any issues.

As long as the integrity of the packages remain intact the Aquatab tablets can last as long as five years.

The AQT100s are ideal for a bug-out bag, international travelers, and emergency kits.

PURINIZE Chemical Free Camping and Survival Water PurificationPurinize Chemical Free Camping and Survival Water Purification Drops

  • Treats as much is 15 water gallons
  • Bottle is 4 ounces
  • Effective against cryptosporidium, giardia, viruses, and bacteria
  • No expiration date
  • Wait time of one hour
  • Sulfate mineral salt is the active ingredient


Okay, so these are drops and not tablets, but they are excellent for water purification hence why they’ve snuck onto our list.

Another reason why we’ve added Purinize here is that they’re a natural method of purification. If the thought of using chemicals to purify your water puts you off then Purinize drops are ideal as they’re chemical free!

PURINIZE Chemical Free Camping and Survival Water Purification

As the market’s only liquid non-chemical water purifier capable of cleansing water from all kinds of freshwater sources, these all-natural drops are made mostly with mineral salts.

Purinize drops are effective in reducing or eliminating more than 200 contaminants, such as industrial and aquacultural chemicals, bacteria, viruses, disinfectants, pharmaceuticals, and heavy metals.

The drops provide a chemical-free alternative to tablets containing chlorine, chlorine dioxide, or iodine.

Purinize drops dissolve water-based impurities, and work best when coupled with a quality filter.

Purinize drops don’t have any chemical after taste and when stored correctly have the potential to last forever.

Water Purification – What history has taught us

Thanks to modern technology, there are quite a few efficient methods that are now used for large-scale water purification. Some of these methods include; UV purification, reverse osmosis, distillation, and desalination, all of which are municipally and commercially used. Although all of these methods are extremely efficient, portability is something they all lack.

When traveling to an area where potable water may be difficult to find; or where heavy rainfall and floods can, and does, contaminate sources of water, water purification tablets are a simple means of making clean safe drinking water a possibility without the hassle of having to boil water or carrying around a filtration option.

Halazone Water Purification Tablets
Halazone Water Purification Tablets

During the second world war, halazone tablets (which were chlorine-based) were added to the accessory packs that soldiers carried with them at all times as a way to disinfect contaminated water. Eventually, the tablets grew obsolete because once opened they had a very short lifespan (the tablets proved to be ineffective 72 hours after a bottle was opened).

Halazone tablets were replaced in 1945 with iodine and other chemicals that were able to last longer, Iodine had a 90-day lifespan on average once a bottle was opened.

The excellent benefits offered by Halazone tablets during the war inspired further research in the following years into improving water purifying tablets, hence why nowadays there are a slew of varieties available, more so now than ever before.

These tablets contain water purifying chemicals that kill all kinds of contaminants, including viruses, parasites, and bacteria.

Simply by dropping such tablets into a specified water amount, they can effectively kill off any number of biological organisms.

Water Purification Tablets – Practical Uses

Water purification drops and tablets are of great use in many different types of situations, including the following:

Survival/Emergency Situations

Needless to say that during an emergency, access to safe drinking water is vitally important – people will not be able to survive for very long without regular hydration.

According to FEMA (Federal Emergency Management Agency), adults need to drink at least a 1/2 water gallon daily (2 liters).

Although it is feasible for someone to go 21 days (504 hours) without food consumption, it is not possible for anyone to go more than a hundred hours without drinking water.

As such, it is imperative to have the ability to purify water if it becomes necessary to do so.

Water Purification of Drinking Water in Survival Situations
Water Purification of Drinking Water in Survival Situations

Heavy rainfall, floods, hurricanes, droughts, and similar natural disasters can disrupt pipes, making drinking water inaccessible.

When these disasters are taking place, humanitarian groups offer people water purification drops and tablets (by way of emergency preparedness/survival kits).

Due to the unanticipated nature of emergency situations and disasters, such events may catch citizens by surprise and leave them unprepared.

Although some places may have plans for disaster relief already prepared, there are no guarantees that these aids will reach everyone within a necessary timeframe.

Keeping water purification tablets on hand will help someone pass 100 hours of dehydration while waiting for help to arrive.

Humanitarian Assistance

Water purifying tablets are also used a great deal for humanitarian reasons.More than 2.7 billion individuals endure water scarcity each year and many of the people in such situations do not have any way to purify their water.

Offering these drops or tablets to people who need them can have a massive impact on the numbers that die each year from dehydration and water borne diseases. Many humanitarian water groups share such tablets to those experiencing water shortages as it is a fast and cost efficient way to alleviate such problems.

Obviously the long-term answer for humanitarian groups is to develop clean sources of water for people who reside in places that suffer from frequent draught conditions or contaminated water.

Offering the education, resources, and infrastructure required for the sake of providing drinkable water is an objective that every humanitarian should strive for.

However, until such sources of clean drinking water and the infrastructures to develop that water exist, water purification tablets provide an efficient and immediate solution.

Military Use

The military often find themselves in situations or locations where the available water is of questionable quality. This is why they have been issuing purification tablets to personell since the second world war. Doing so ensures troops are always able to drink potable water whenever they need it.

Military Use of Water Purification Tablets
Military Use of Water Purification Tablets

Not only are troops in a position to help themselves when it comes to making water safe to drink but they are also very often in a position to offer assistance to people without access to safe water, as is the case in many warzones, by offering to give them water purifying tablets.

Camping, Backpacking, or Outdoors

Water purification tablets are also widely used by those that participate in outdoor activities like camping and hiking, and prove themselves to be invaluable time and time again in situations where there is little to no consumable water.

By harvesting some river/stream water or rainwater, inserting tablets into a container, and letting the liquid sit, waterborne illnesses and dehydration can be prevented.

Although a number of outdoor enthusiasts might keep a compact water filter with them during a trip, the use of purification tablets, alongside using a filter, will offer better protection from pathogens.

Compact water filters can sift out dangerous debris, bacteria, and parasites, but sometimes, the filters may be too broad and as such, some viruses will be able to seep through.

This is where water purifying tablets come to the rescue.

What Water Purification Tablet Types Are Available?

Tetraglycine Hydroperiodide (Iodine)

  • 6-year shelf life
  • Effective for 50-minutes against giardia, viruses, and bacteria
  • 30 to 50-minute wait time

The chemical compound known as iodine – which may come in the form of a crystal, tablet, or liquid – is mostly used to purify water. Iodine is particularly effective at eradicating viruses, parasites, bacteria, and other micro-organisms.

For absolute water purification, the mixture should sit for a minimum of 30 minutes once the iodine has been immersed in the water.

Temperature has a significant impact on how effective iodine is at purifying water. The purification process can take a while with cooler water, as opposed to warm water. Furthermore, the water quality determines the quantity of iodine that is necessary. The more murky the water, the more it requires greater levels of iodine, and vice versa.

If there are visible particles in the water, strain it before iodine is added, or as suggested, run it through a filter first.

Common viruses and bacteria (such as salmonella, cholera, and E. coli) require a minimum of 30-minutes as well as a 75°F temperature for absolute purification.

Iodine is quite effective at purging giardia when it can sit for a minimum of 50 minutes – though it will be ineffective when cryptosporidium is involved.

The taste of iodine might be apparent when it is used to purify water. There are pills available that can purge the iodine taste from water after purification.

For most people, water purified by iodine is safe to drink and without side effects. The side effects reported by those who have experienced them include metallic aftertastes, nausea, and headaches.

People who struggle with thyroid infections, pregnant females, and women over the age of 50 are encouraged to speak to a doctor before consuming iodine-purified water.

An iodine tablet’s shelf life is about 6 years, on average, there are tablets that can last a year longer, including the IOSAT130 mg tablet.


Sodium Dichloroisocyanurate (Chlorine)

  • Five-year shelf life
  • Effective for 45-minutes against giardia, bacteria, and viruses
  • 30 to 45-minute wait time

Using chlorine to purify water is a process known as chlorination, and it has been used for more than a century.

Chlorine is particularly effective at eliminating viruses and bacteria that can result in diseases (like cholera, gastroenteritis, typhoid, and dysentery).

When water is disinfected by chlorine, it first destroys microorganism cell membranes, allowing the chlorine to penetrate and disrupt its cells’ DNA activity and respiration.

Used in conjunction with adipic acid and sodium bicarbonate (among other effervescent salts), these tablets quickly dissolve and purge a large amount of viruses and bacteria.

Chlorine isn’t effective at eliminating cryptosporidium as it struggles to break down the shell protecting it and when it comes to eliminating giardia, chlorine is only partially effective.

Tablets that are chlorine-based are superior to liquid chlorine formats because of the extra effervescent salts they contain, which enhances their effectiveness. It is also worth noting that the liquid form that can degrade over time.

When purifying water with chlorine, add a proportionate quantity of water,then let it sit in a sealed container for approximately a half-hour, for it to be effective against giardia, let the mixture sit for a minimum of 45 minutes.

The US Environmental Protection Agency claims that, when consumed in small amounts, it is safe to drink chlorinated water.

Be mindful that chlorinated water does come with an aroma that smells like bleach, this scent will go away if the water container is left open.

Chlorine tablets have a 5-year shelf life, on average.


Chlorine Dioxide

  • Four-year shelf life
  • Effective against cryptosporidium, giardia, viruses, and bacteria
  • 4-hour wait time

Tablets containing Chlorine dioxide are the strongest purification tablets. It will eliminate a variety of pathogens, such as viruses and bacteria. It can also kill parasites like giardia lambria and cryptosporidium.

With regards to individuals who may suffer side effects from taking water prurified using tablets or drops, tablets containing chlorine dioxide don’t give as many of the side effects that chlorine and iodine tablets do. Nor do they change the flavor of water after completion of the purification process.

Chlorine dioxide is more effective against cryptosporidium and giardia than chlorine or iodine tablets are, with that said, for the purification process to be effective, the water will still need a minimum of four hours to completely purify.

Oxidation is a big part of this chemical’s effectiveness. The cell membrane of a micro organism is broken down by the chemical, which then eradicates the cytoplasm with the use of strong amino acids.

Although the giardia and cryptosporidium have protective shells, they tend to be chlorine and iodine-resistant (to an extent), they are not as protected from chlorine dioxide, though.

Tablets containing Chlorine dioxide are generally activated once the tablets make contact with moisture or water.

According to manufacturers of tablets containing Chlorine Dioxide will, when stored correctly in a sealed air and moisture tight container, last for four years from the date of manufacture.

Water Purification Tablet Benefits


Perhaps the biggest benefit that can be attached to water purification drops and tablets is that they are very simple to use and are also convenient.

Tablets will either be packed loose in a small compact bottle or in a foil wrapper, making them easy to carry in a pocket, backpack, or purse.

There is very little difference in the way each brand is used; a certain number of tablets or drops are added to a specific volume of water, then a certain period of time waiting must be observed whilst the chemicals do their work.

Protection from Viruses and Bacteria

Water purifying tablets are used to eliminate microbiological contaminants like viruses, parasites, and bacteria.

Certain microorganisms cannot be seen by human eyes, and can lead to alarming health issues once ingested.

Water purification tablets can kill off common bacteria like cholera, salmonella, and E. coli, which happen to be the main causes of a large number of waterborne illnesses.


Tablets are on the whole extremely light even when packed in little bottles, and will have no real impact upon the weight of your carrying load, making them no problem at all to carry.


Water purifying tablets are inexpensive, relatively speaking, when stored properly, they have a shelf life that can potentially last for years which in itself is is beneficial in minimizing tablet costs over the long term.

What Are Some of the Water Purifying Tablets You Recommend?

It’s makes sense to use multiple water purification methods, youbcannot be careful enough right? Purification tablets work best when they are paired up with quality water filters like the Lifestraw or the Sawyer Mini.

Specific protozoa species like cryptosporidium usually have a strong resistance to chemical purifiers, however, they are too big to go through many water filters including the two just mentioned above.

Always keep this in mind when choosing a purification tablet.

In Closing

Having multiple purification options is always recommended as a number of pathogens are resistant to certain chemical purification methods. This is where quality water filters with 1-micron filtering would be beneficial, as they are capable of blocking bigger parasites that may get through, this is particularly true of Cryptosporidium.

If you have read the entire article above you may be thinking that there is very little difference between each water treatment, and in all fairness you are probably right. However, there is enough of a difference not to just go out and buy any the first one you find. You definitely need to weigh up your personal needs and preferences before making your final choice.

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