How Many Water Purification Tablets Do I Need for Drinking Water?

There is no greater buzzkill of your outdoor adventure than suddenly realizing you didn’t pack enough drinking water. The good news is that if you are out in nature, there is a pretty good chance you will find a stream or a spring with water for quenching your thirst. But such water is usually full of disease-causing microorganisms so you might want to purify it first before breaking it. And that’s where water purification tablets come in handy.

Whether they use chlorine or iodine as the active ingredient, nearly all water purification tablet manufacturers require you to use 1 tablet per liter or 32 ounces of water to clean and disinfect water. Be sure to check the instructions for your specific product used for proper dosage as well as the necessary wait time before drinking the water.

Read on for more information on the science behind water purification tablets, how to use them, and the best ones to check out for your next trip.

The science behind water purification tablets

Water purification tablets are designed to disinfect and instantly make water healthy and safe to drink. Simply drop one or two in your water bottle, allow it to sit for about twenty minutes, and your water will be safe to drink.

With a water purification tablet, you can rehydrate anywhere, anytime.

What are water purification tablets and how do they work?

Water purification tablets are concentrated versions of chemicals that release certain agents into the water to quickly eliminate any pathogens waiting inside to infect or hurt those who drink from it. Microbes that exist in unpurified water can be extremely harmful to humans.

Water can contain all kinds of contaminants, including escherichia coli bacteria, fecal matter, fecal coliforms, giardia bacteria, and even cryptosporidium, a type of poisonous mold.

Many microorganisms also float within the water and can trigger serious digestive issues, fevers, and viral infections. Many people die from drinking tainted water every year, and water purification tablets are designed to be an on-the-go solution to counter this.

The exact formulation of water purification tablets depends on the type of tablet you are using. Most use a form of free chlorine that is harmless to you to drink but floats through and kills or neutralizes any harmful or dangerous bacteria in the water. Some will even combine chlorine, iodine, and chlorine dioxide to create a powerful trio of water treatments.

These chemicals fight off every bacteria, parasite, or virus contained within your water and make your water completely safe to drink.

How to use a water purification tablet

Using a water purification tablet depends on the exact instructions of each brand of water purification tablet, but the general premise remains the same across the board. First, you must collect and measure the amount of water you are trying to purify. The more water, the more tablets you are going to need.

A general rule of thumb is one water tablet for every liter of water (approximately 32 ounces or one Nalgene water bottle, for scale).

CAUTION: water purification tablets are only effective against pathogens but will not remove heavy metals or any other natural sediment in the water. With that in mind, you may want to also run your water through a filter before you drop a purification tablet into it.

For best results, put your water into a container that can be sealed and drop one or two tablets in, depending on the size and potential contamination of the water. Shake the water bottle until the tablet dissolves completely and then set it down away from direct sunlight and let it rest for a while. You should let your water rest at least 30 minutes but potentially up to an hour before you begin drinking it.

You’ll know your water purification tablet has worked when there is no more trace of the tablet or its dissolved particles in your water and at least half an hour has passed. You may not notice a change in taste, or there might be a slight taste of chlorine (similar to drinking pool water), but overall your water will not be heavily affected, and you can continue to drink it safely.

How long do water purification tablets last?

The nice thing about water purification tablets is that their benefits don’t expire. Once you drop a water tablet into your water, its benefits are permanent. There is no chance of microorganisms regenerating or continuing to build and infect your water. Y

ou can drink the water you put the tablets into for several days, and it would still be effective and protected against waterborne diseases.

The overall benefit of these long-lasting water purification tablets is that you don’t need sophisticated and time-consuming equipment repetitively applied to your water in order to keep it clean.

Once your tablet has been dropped in, your water is good to go, permanently and always. No electricity, no retreatment, and no additional filters needed.

For this reason, it is recommended that every home keep a store of water purification tablets on hand just in case a disaster happens and access to clean water becomes challenging.

What are the best water purification tablets?

Katadyn Micropur MP1

The Katadyn Micropur MP1 tablets are widely acclaimed because they kill all microorganisms, including fatal and often unnoticed cryptosporidium. These prioritize functional and powerful water purification that offers a decent, neutral taste with no irritation or side effects, unlike other chemical-heavy purifiers. They’re relatively affordable and easy to pack and use, making them a popular and well-loved choice by outdoor lovers.

Potable Aqua Chlorine Dioxide Tablets

These are a great choice for people looking for simple and effective water purification tablets that are easy to pop into your water on a hike and get back on the road. There’s no strong smell or aftertaste here and they’re quickly effective, making them great for hikes or water emergencies.


These famous water purifying tablets are known the world over for their affordable effectiveness. They’re incredibly affordable and effective and pack quickly and lightly into your belongings. There’s no aftertaste except for a mild chemical smell that fades quickly. They deal with every pathogen except cryptosporidium but are definitely the best bargain tablet.

Potable Aqua with PA+ Plus

These powerful iodine tablets are a two-part system that drops neatly into your water with zero noticeable difference. No strong taste, no unbearable smell, just quick-treated water that’s safe and easy to drink and enjoy.

You can buy these anywhere and affordably, making these a great powerhouse of portable water purification tablet treatments.

What else can purify water?

Water purification tablets are generally the best way to quickly and efficiently purify your water, but if you’re in a pinch or your supply runs out, there are a few different other proven methods that can help you establish clean and reliable drinking water.

One of the most common methods of purifying water is boiling. Just put your water in a pot or other device and heat it until it boils. This process cooks and steams out any diseases or microorganisms, ensuring the same benefits as water purification tablets but without the tablets themselves.

If you have pure chlorine, you can also put a few drops into your water. Some people will use household bleach with 5% chlorine content as a water purifier in a pinch. This should only be done in emergencies or dire conditions where nothing else is available. In emergency situations, bleach can be an effective method of water purification because it kills bacteria and germs in the water.

Iodine can also be added in tablet or liquid form to help remove bacteria and viruses. However, it leaves behind an aftertaste that may make the water less desirable.

Final thoughts

Water purification tablets can truly transform the way you hike and interact with the wild. Remember to carry them on your next adventure and you will not have to worry about drinking contaminated water.

However, the tablets are only suited for removing pathogens but they will not deal with heavy metals and other chemical impurities. Such impurities are not an issue for most wild water but the story is different for household water.

That’s why you should rely on a water filter for your home drinking water and only use tablets when outdoors or when traveling overseas.

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