Key Questions to Ask When Ordering Chlorine Dioxide Water Purification Tablets

05, Jun. 2025

 

Best Water Purification Tablets & Drops - TruePrepper

Water is a necessity for survival, but it’s also a necessity to have it clean enough to drink. We’ve all experienced food poisoning a few times in our lives, and impure water will make that seem like a breeze when you get sick from it. The best water purification tablets make cleaning water quick work and will get you back to other important tasks in an emergency or survival situation.

If you want to learn more, please visit our website.

There are only a handful of brands and types to choose from when it comes to tablet-form water purifiers. Even still, you need to know what you can rely on when you need it most.

This is where we come in. We’ve researched the best water purification tablets, tested each of them, and now the results are in: the overall best, portable, budget, drop, and an option with unlimited shelf life. If you need to get clean water that will keep you going in a survival situation, one of our suggestions will help keep you hydrated.

Contents (Jump to a Section)

Potable Aqua (with PA Plus) water purification tablets hit our top spot since they get the job done at the right price. These tablets are effective, fast, and don’t leave that funky iodine taste or stain that cheaper one-shot tablets have. They are lightweight enough to add to any kit and very simple to use. After just 35 minutes, you’ll have water that is ready to drink when it filters out bacteria and Giardia lamblia.

Specs

  • Treatments: 50 tablet pairs
  • Total Water Treated: 25L
  • Time Required: 65 minutes
  • Purification Method: Iodine
  • Weight: 2.24 ounces

Many people complain about the taste of Potable Aqua, but that would be the single tablets rather than this two-tablet solution with the extra neutralizing tablet. This makes the taste of the water much more palatable. I’ve been using this two-tablet product for so long that I had forgotten that the single tablet was sold on its own. For the small price difference, it is worth the investment to clear the water up and neutralize the taste.

Add Potable Aqua PA+ Tablets to your kits and don’t look back. I use them in my own kits and am not surprised to see that they easily beat out the competition when we put them to the test.

Not only are these the best tabs to use in your mobile kits, but they are also simple and thorough. You use one tab for one liter and let it react for 30 minutes to 4 hours (if the water is cold and dirty), which is one of the simplest reactions you can find for chemical water purifiers.

Specs

  • Treatments: 20 tablets
  • Total Water Treated: 20L
  • Time Required: 30 minutes
  • Purification Method: Chlorine Dioxide
  • Weight: 0.35 ounces

Many other treatment types require mixing, or multiple tablets, or aren’t as aggressive at cleaning up the water. The chemical disinfectant leaves hardly any trace of taste, and it performed great in my taste test.

They have an extensive shelf life and are the easiest option to spread between your family’s bug out bags and other survival kits. I pop off several packs for everyone’s bags as they are virtually weightless and take up hardly any room.

Pick up some Katadyn Micropur MP1 Water Purification Tablets for any of your kits for the best water treatment solution in tablet form, and you won’t regret it.

Bleach is the most recommended emergency water treatment because it is so widely available, inexpensive, and one jug can treat thousands of liters of water.

Specs

  • Treatments: 81 fl. oz jug
  • Total Water Treated: Approximately 14,000L
  • Time Required: 30 minutes
  • Purification Method: Chlorine Dioxide
  • Shelf Life: 1 year
  • Weight: 88 ounces

There are some drawbacks to bleach, though. The shelf life isn’t what you want for stockpiling, the taste it infuses in water can be tough, and it’s not ideal to drink bleach-purified water for long periods. Boiling is the emergency purification method that’s preferred over bleach, but that’s not always possible.

Pick up some standard Clorox Disinfecting Bleach for cheap and convenient water treatment during an emergency.

Aquamira is a bit different (and it’s not a tablet), but we felt it was a worthy inclusion in our testing since so many people suggested it. It did not disappoint!

Specs

  • Treatments: Pair of 1 fl. oz bottles
  • Total Water Treated: 112L
  • Time Required: 20 minutes
  • Purification Method: Chlorine Dioxide
  • Shelf Life: 4 years
  • Weight: 3.5 ounces

Use the bottle droppers to drip 7 drops into the included mixing cap, and then let the reaction happen for 5 minutes. The reaction will turn the mixture yellowish. Pour that mix into a liter of water, shake or stir, and then let it sit for 15 minutes. After that time has passed, you’ll have drinkable water. This is the fastest purification method I tested and is even quicker than the tried-and-true boiling method!

The downside to these is that they are liquid, and can have some related problems. For starters, you have to babysit the drop mixture while it reacts, so you can’t be on the move or you risk spilling it. Also, the bottles are squeeze bottles, so you can get some leaks if you aren’t careful where you pack them. After my tabletop testing, I found it best to include these as part of my home water storage solution rather than a mobile kit. They are significantly better tasting than bleach mixtures and can scale to large storage containers too.

Pick up some Aquamira Water Treatment Drops for fast water treatment at home.

Purinize is a flocculant, so it’s similar to Chlor-Floc and P&G Purifier of Water. That’s where the similarities end, though, since it uses natural minerals as the coagulant agent, giving it an unlimited shelf life.

Specs

  • Treatments: 2 fl oz bottle
  • Total Water Treated: 40L
  • Time Required: 60 minutes
  • Purification Method: Flocculation
  • Shelf Life: Unlimited
  • Weight: 2.4 ounces

Pick up some Purinize Water Treatment Drops to stockpile unlimited water treatment on the shelf.

Comparison Table

The Tablets We Compared

Our research narrowed the field down to several purification tablet brands and types that we tested: Potable Aqua, Coghlan’s, Ef-Chlor, Aquatabs, P&G, Katadyn, ‎Chlor-Floc, Colemans, and more.

Some of these brands use the same chemicals and concentrations to develop their tablets, so we ended up testing quite a lot of them, looking at the differences in quality, taste, packaging, etc. You can see our full list of review criteria below in the What to Look For section, with an explanation for each.

We did not consider any in-place purifiers, membrane purifiers (like straw filters), UV purifiers, or powder, and focused entirely on water purification in tablet or drop form. You can find examples of each of those that work well, but the purifiers with small packaging are great for portable kits.

The best filters can be found in their own review: Best Survival Water Filters.

A few that we compared were the same product and manufacturer, just different brand labels.

We’re always looking for new and better equipment, so if you have a purification tablet you swear by let us know down in the comments. We review most of our tested gear annually, so we can always get it in the next roundup and see if it makes the cut, and we can see if it will beat out our top picks.

What to Look For

The best water purification tablets have several important features to look for:

  1. Value
  2. Effectiveness
  3. Speed
  4. Shelf Life
  5. Versatility

When you get the right blend of these, you can find reliable tablets that will keep your water purified in an emergency. Below, we break down what each of these features means for truly dependable tablets that you can trust with your life:

Value: Cost vs. Benefit

The amount of money you spend on something like purification tablets shouldn’t blow out your budget. Having one is better than having none, but the same applies to other tools and gear you may need for an emergency. Budget according to your risk and your needs, rather than just spending lavishly.

On the flip side, you don’t want to go too cheap. Luckily, every tablet we tried was effective when the instructions were followed correctly, but there are still benefits to spending more. Cheap tablets require more time to purify the water and often leave a chemical taste. Don’t get too frugal when it comes to something you will rely on in an emergency.

*price at time of latest review update

With competitive price and timely delivery, Xiuyuan sincerely hope to be your supplier and partner.

You never want to spend too much money on one resource, especially something like tablets. It’s better to diversify your tools and preparedness gear to make sure you are covered for a wide range of scenarios. There is a sweet spot where you get high value out of the best features with not too high a price, which is where our top pick sits.

Effectiveness

The effectiveness of a purification tablet is tied to the contents and quality of the tablet. Several different chemical compounds can be used to purify water, but only a few of them are available in tablet form. Water purification tablet chemicals typically include:

  • chlorine
  • chlorine dioxide
  • iodine
  • NaDCC
  • Flocculants (various)

These vary in effectiveness and have their strengths. Chlorine dioxide is the most powerful of the three listed here and is one of the most effective at killing a wide range of microorganisms, including viruses and protozoans.

Some flocculants don’t use chemicals at all and use minerals as the coagulation agent.

Besides the treatment method and chemicals used, I also looked at how much water could be treated with the entire package, and then rounded out the effectiveness score by taste-testing the options.

Treatment Capacity

The highest capacity treatment you can get is bleach. No tablet or drop comes even close to the vast amount of water a jug of bleach can purify for only a few bucks. Still, it’s a worthwhile cost comparison to see how the tablets and drops stack up against each other.

That’s why I prioritized the treatment volume in the comparison table.

Taste

A few of the treatment options can leave the water with an odd flavor. Some iodine treatment tablets also come with iodine neutralizer tablets to eliminate the unpleasant taste with a two-part tablet treatment. Chlorine tablet-treated water can be left exposed to air to allow the chlorine to evaporate over time to reduce the odd taste.

Unpleasant taste isn’t the only concern. Those with thyroid conditions, iodine allergies, and pregnant women should avoid iodine water purification tablets.

Speed

Speed is important in an emergency, and important for clean water in an emergency. Four hours becomes a much longer time to wait for water purification than 30 minutes, since water purification tablets are an emergency solution.

In-place and bulkier water purifiers are expected to take a little longer, but water purification tablets are meant to be fast and easy. If you wait around all day for purified water, you may as well be boiling water to purify or using other solutions. In the military, we called this a ‘fire and forget’ method – add a tablet to your water bottle and keep on moving. Then you can drink it after a short time limit of at least 30 minutes. This lets you stay mobile and concentrate on other tasks.

The Potable Aqua Chlorine Dioxide tablets came in at the top end, requiring a full four hours of treatment time. This was odd, since the other chlorine dioxide options, like the Micropur and Aquamira, were very fast.

Some tablets could be cut short- you could cut the PA+ treatment time roughly in half if you needed to, but you’ll end up with that rough iodine taste. Flocculants were also fast, but require additional straining after the treatment period to filter out the coagulants.

Shelf Life

Some water treatments degrade quickly, even in their original packaging. As a baseline, bleach gives us only 18 months from the manufacturing date before it starts to degrade. Unfortunately, liquid bleach isn’t very effective to stockpile unless you can cycle through the amount you typically use using FIFO (first in, first out) storage.

Water treatments with longer shelf lives can buy you plenty of time, though, with the Purinize drops not even having a shelf life since it only uses shelf-stable flocculating minerals. Here are the rest of the shelf limits for water treatment tablets and drops:

Versatility

The packaging and composition of purification tablets can provide some versatility when you need to use them outside of your regular function or in unique scenarios. Individually packaged tablets are amazingly convenient for bug out bags and everyday carry.

The Micropur tablets are the lightest tablet solution and are very small. Two tablets in their packaging didn’t even register on our scale with the lowest unit (grams) selected.

How to Use Water Purification Tablets

Water purification tablets are very easy to use, and they come with instructions printed right on. Take care to read them, and it’s hard to go wrong. You’ll need to know how much water you are purifying, usually listed in liters.

Before you start tossing tabs in, you’ll also need to filter out any debris and sediment in the water. This is not necessary with all water purification tablets, but it is good practice since it will speed up the process and require fewer tablets.

Once you’ve discovered how many tablets you need to treat your membrane-filtered water, you just add the tablets and wait for the time listed on the packaging.

Who Needs Water Purification Tablets?

The CDC and FEMA hope everyone has water purification tablets on hand. There is not enough in the strategic stockpile for everyone, and distribution would be a massive challenge. Membrane filtering isn’t clean water, and you’ll need potable water no matter what emergency you encounter.

This is why you’ll find it suggested for almost every kit.

Water purification tablets are essential for:

  • Home Survival Kit
  • Bug Out Bag
  • Get Home Bag

We suggest at least a few tablets for these kits as well:

  • Everyday Carry
  • Car Kits

Of course, you can always use the tablets for things beyond emergencies and survival kits too- like rugged camping and bushcraft. We actually encourage it- don’t let them sit in your bags and kits without knowing how they work or how to use them properly.

Sources and References

All of our experience and the testing we do to determine the best water purification tablets is useless without listing our research sources and references. We leaned on these for the book knowledge that we paired with our hands-on testing and practical military and prepping experience:

Benzoni, T., et al. (). Bleach Toxicity. StatPearls. Treasure Island, FL. Accessed through the National Library of Medicine. (Source)

Gerba, C., et al. (). Efficacy of iodine water purification tablets against Cryptosporidium oocysts and Giardia cysts. Wilderness & Environmental Medicine. Volume 8, Issue 2, Pages 96 – 100. (Source).

Nakamura, S., et al. (). The impact on health and risk factors of the diarrhoea epidemics in the Bangladesh floods. Public Health. Volume 116, Issue 2, Pages 68 – 74. (Source)

Powers, E. (). Efficacy of Flocculating and Other Emergency Water Purification Tablets. Army NATICK Research Development and Engineering Center. (Source)

Schaub, S., et al. (). Evaluation of the Military Effectiveness of Chlor-Floc Water Purification Tablets for Treatment of Waterborne Micro-Organisms. Army Biomedical Research and Development Lab. Fort Detrick, MD. (Source)

The Final Word

Water is essential to survival, so you’ll need several ways to store, collect, and treat water in a wide range of situations. Whether you are staying put to bug in or hitting the road to bug out- water purification tablets should be a part of your survival kit.

To go along with solid treatment tablets, you should also consider a few other water storage solutions:

  • Best Rain Barrel for Prepping and Emergency Water Storage
  • Best Siphon for Pumping Water, Gas, and Other Liquids
  • Water Storage Calculator

We presented quite a lot of information, but as always: if you have any questions, let us know and we would be happy to help. Our research and testing found that the Potable Aqua Tablets are the best option given their value, effectiveness, speed, taste, and versatility. If you take our suggestion and grab these purification tablets, make sure you try them out and know how to use them before an emergency.

Keep exploring, stay prepared, and be safe.

If you want to learn more, please visit our website Chlorine Dioxide Water Purification Tablets.

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Frequently Asked Questions - Ef-Chlor Water Purification Tablets

Each Ef-Chlor Tablet contains a measured dose of Sodium Dichloroisocyanurate, commonly referred to as NaDCC. When added to water Ef-Chlor dissolves to release a measured dose of Hypochlorous Acid (free available chlorine) that is universally recognized as a safe and effective water disinfectant.
Yes, Ef-Chlor water purification tablets efficiently work with well water, borewell water, dirty water, contaminated water or municipal water supply. Ef-Chlor is the world’s no. 1 best water purification tablet widely used for water disinfection / water purification method across the world.
Ef-Chlor having many forms of NaDCC tablets which are slightly different for specific amount of water treatment. You can checkout the range of best water purification tablets which can purify the water from 1 litre to 50,000 litres of water.
Get » Water Purification & Disinfection Products
In most situations, water treated with Ef-Chlor is safe to drink after 30 minutes. In some temperatures and conditions, 60 minutes might be recommended. Please see the dosage chart included with each product for more information.
You can keep 7 days in any sealed container or spray bottle. 24 hours in an open container / bucket. If tblat and broken, no problem just put the pieces in the container and add water.
Ef-Chlor contains Sodium Dichloroisocyanurate (NaDCC), a chlorine releasing compound. This compound is used in 67 countries for water purification purposes. The World Health Organization, Red Cross and Bureau of India Standard have recommend NaDCC for the purpose of water purification. NaDCC is used by all state governments in India for water purification since approximately the last 5-7 years.
For Water Purification And Disinfection
If the water is relatively clear / clean then a dosage rate of 2 mg of chlorine per liter can be used. If the water is dirty it should either be filtered through a cloth such as a t-shirt or allowed to sit until the sediment settles down and then decant off the clear water. Where dirty water needs to be treated or the water is suspect 5 mg of chlorine per liter dosage rate should be used.
For Surface Disinfection In Kitchens
Dose at a concentration of 100 mg of chlorine per liter
For Fruits And Vegetable Disinfection
Dose at a concentration of 300 mg of chlorine per liter
For General Surface Disinfection In Clinic / Hospitals
Dose at a concentration of 200 mg of chlorine per liter
For High-Risk Areas Hospital, Blood and Body Fluid Spillages 
Dose at a concentration of mg of chlorine per liter
Explore All  » Water Purification & Disinfection Tablets
Ef-Chlor water purification tablets are also very important when engaging in outdoor activities such as hiking and camping and might prove a very important accessory especially in areas with little or no potable water. By simply harvesting some rainwater or water from a stream or river, dropping some tablets into the bottle, and allowing the water to sit for a couple of minutes can prevent dehydration or water-borne diseases.
Yes, Ef-Chlor can be used to make water safe for washing fruits, vegetables, leafy greens and other products. Each Ef-Chlor tablet can be used to purify 20 litres of water . For higher dose if required, please contact us for more information.
Yes, Ef-Chlor is the most reliance and safest treatment for water borne diseases / germs. Ef-Chlor is the best water purification tablets for the prevention of  water borne diseases worldwide, these NaDCC tablets are fight against list of identified species:
  • Bacterial Species (E.Coli, Shigella, Salmonella etc.)
  • Virus Species (Rotavirus, Hepatitis, Poliomyelitis)
  • Fungal Species (Candidiasis, Fungi, Aspergillosis)
  • Protozoan Species (Entameoba Histolytica, Giardiasis, Cryptosporidiosis, Cyclosporiasis)
Ef-Chlor prevent all communicable water borne disease. These are fast acting effervescent tablets that kill microorganisms in the water to prevent cholera, typhoid, jaundice, diarrhea, dysentery, giardiasis,  polio, infantile diarrhea by rotavirus, candidiasis, bacillary dysentery, skin infections, escherichia coli / e.coli bacteria infection, urinary tract infections, and other water-borne diseases. Ef-Chlor even helps to avoid all Gram Positive and Gram Negative Bacteria, Virus and Fungi. In addition, Ef-Chlor destroy biofilms that are found on pots, vessels and tanks, a major source of e.coli bacteria.
No, Ef-Chlor is not a medicine. The World Health Organization (WHO) classified the compound NaDCC (SODIUM DICHLOROISOCYANURATE) as a food additive.
Yes, Ef-Chlor tablets are safe to handle and store. Unlike other water purification treatments such as Iodine or Chlorine Dioxide, Ef-Chlor tablets do not require gloves, protective eyewear, or any other protective gear to be used.
Yes, Ef-Chlor is the world’s no.1 water purification tablets or NaDCC based chlorine (SODIUM DICHLOROISOCYANURATE). These are fast acting effervescent tablets that kill microorganisms in the water to prevent cholera, typhoid, jaundice, diarrhea, dysentery, giardiasis,  polio, infantile diarrhea by rotavirus, candidiasis, bacillary dysentery, skin infections, escherichia coli / e.coli bacteria infection, urinary tract infections, and other water-borne diseases. Ef-Chlor even helps to avoid all Gram Positive and Gram Negative Bacteria, Virus and Fungi. In addition, Ef-Chlor destroy biofilms that are found on pots, vessels and tanks, a major source of e.coli bacteria.
Ef-Chlor tablets are effective against Giardia when used as directed. Usually a double dose is required in very cold water (5°C).
Ef-Chlor tablets are not effective against Cryptosporidium when the cyst is in the oocyte stage of its life cycle. Cryptosporidium is however not considered to be a common cyst.
If Cryptosporidium is suspected, boil the water for 1-3 minutes depending on elevation or filter to level of 1 micron absolute and then treat with Ef-Chlor tablets to inactive remaining bacteria and viruses that filtration does not generally remove.
Water contains high amounts calcium, iron and magnesium. Ef-Chlor may react with these minerals and form harmless salts of chlorine.
No. Ef-Chlor only purifies water of all pathogens and prevents all communicable water borne diseases. Ef-Chlor does not address the issue of Arsenic or Fluoride. 
Ef-Chlor takes less than 1-2 minutes to dissolve in water, and it takes 30 minutes for the chlorine to react and fully treat the water. The water becomes fit for drinking, and free from all water borne germs after 30 minutes.
No, There is no need to stir the ef-chlor tablet after it is added into the water. The tablet dissolves in the water and become gems free and safe to drink after 30 minutes.
The following general precautions are recommended when using  Ef-Chlor NaDCC Tablets:
  • Keep out of reach of children
  • Do not mix with other products
  • Store in a cool, dry place
  • Do not swallow tablets
  • If  tablets are swallowed, drink milk and seek medical advice immediately.
In case of swallowing Ef-Chlor tablet or any such accident, one must drink plenty of milk. Slight drowsiness may occur. Although Ef-Chlor tablets are non toxic, one should always seek medical advice at the earliest opportunity. Do not induce vomiting.  
No, unlike other water purification treatments such as Iodine or Chlorine Dioxide, Ef-Chlor Water Purification Tablets will not discolor the water or leave an unpleasant taste. Ef-Chlor NaDCC Tablets works very differently from traditional chlorine, and as such, it is very difficult to taste any chlorine in treated water with ef-chlor. Usually less of a chlorine taste in water treated with Ef-Chlor water purification tablets as compare to any municipal tap water.
Boiling water helps kill bacteria as well as other disease-causing microorganisms like Giardia Lambia and Cryptosporidium Parvum, which are commonly found in rivers and lakes. However, it is an expensive, time consuming, unsure and environmentally damaging method of treating water.
Yes, Ef-Chlor water purification is better than common electric water purification systems, especially in rural areas for these reasons: 
  • Water purification systems work on electricity, filtration membrane and/or ultraviolet light. The ability to kill germs via these systems is on running water and not on stored water.
  • Stored water has chances of becoming contaminated once again after filtration, due to Biofilms in the container vessel – therefore the use of ef-chlor is recommended for filtration at point of consumption for utmost safety. 
  • Over a period of time the ultra violet bulbs looses its photon power like any another bulb. This will reduce the efficacy of the system.
  • The ultra-filter gets clogged over period of time. This clog will have biofilms and readily produce bacteria.
These issues require periodic checks in the purification system, which seldom happens. Surveys show that once installed most people do not car for maintenance. This is a major reason people suffer from Sore throat and Diarrhoea in spite of using such systems.
If used in the recommended dosage, Ef-Chlor is very unlikely to cause any kind of allergic reactions. Ef-chlor should not be used by persons who are hypersensitive and/or inherently allergic to chlorine products. 
No, Ef-Chlor tablets do not contains iodine. Iodine has been found to cause a number of side effects and health hazard when used a water purification agent, notably when used by pregnant woman and/or when used on long-term basis.
No, Ef-chlor does not react adverse with any metals. It will react the same way, and effectively purify the water, regardless of the material of the container.
Ef-Chlor tablets are manufactured and sold by Hind Pharma. Ef-Chlor tablets can be purchased from Hind Pharma or Authorized Distributors.