Facts and tips

Chemical additives to purify water that are mostly used by fishermen, hunters, hikers or other outdoors enthusiasts are iodine and Chlorine. Iodine and chlorine are very good in killing the giardia parasite. However, they can’t eliminate the cryptosporidium parasite from the water. These parasites can occur in water that is contaminated with feces from animal waste.

Ingredients of water purification tablets

Water purification in the mountains

Using water purification tablets in the mountains

The main chemical ingredients in water purification tablets are chlorine, chlorine dioxide or iodine. These chemicals kill bacteria, viruses and parasitic protozoans in contaminated water.

The most widely used chemical ingredient is chlorine. The advantage of chlorine is that water is quickly purifiet. The disadvantage is that water, that’s treated with chlorine,will become contaminated again during prologe storage.

Chlorine dioxide
The most effective ingredient in water purification tablets is chlorine dioxide, it kills a wide range of microorganisms. Unlike chlorine, chlorine dioxide doesn’t chlorinate. It works through oxidation and penetrates bacteria cell walls and reacts with vital amino acids in the cytoplasm of the cell to kill the organism. The disadvantage of chlorine dioxide is that it takes longer to purify the contaminated water than iodine or chlorine. The tablets that contains chlorine dioxide only produce chlorine dioxide when they come into contact with water or moisture. When the tablets are sealed in an airtight package they can be stored and used when needed. Chlorine dioxide is also used in water treated for municipalities.

Iodine is required for a proper thyroid function, but it can effect the thyroid function if you use too much or too less iodine. Iodine is also added to table salt in many countries around the world to insure the right amount of dietary iodine.

Iodine is rapidly metabolized and cleared from the body and the intake of iodine are accommodated by the normal thyroid gland. Iodine tablets can be used by persons with a normal thyroid function for a short time (six weeks or less). You must not use iodine tablets if you have thyroid problems, an iodine allergy or when you are pregnant.

Thyroid conditions

Thyroid problems can seriously affect metabolism and body function. Iodine is an essential element that enables the thyroid gland to produce thyroid hormones. But, if you are using too much iodine it leads to hypothyroidism and autoimmune thyroiditis.

If you have a thyroid condition, you should not use iodine.
If you have an iodine allergy or when you are pregnant, you should not use iodine.

Temperature of the water

If you use water purification tablets you have to be careful of the temperature of the water you are purifying. If the contaminated water has a temperature of about 75 degrees Fahrenheit you need at least 20 to 30 minutes for purification. If the contaminated water has a temperature of about 40 degrees Fahrenheit
you need at least one hour to purify the water. So, colder water will take longer for purification.

Warm the contaminated water in the sun before adding the water purification tablets.

Filter water

Before using the purification tablets you need to filter cloudy water or water with sediment. You can use a coffee filter, towel or handkerchief to filter most of the dirt out of the water.

Taste of the water

If you used water purification tablets to purify contaminated water the taste of it can be quite different compared to the water that you are used to. To improve water taste you can add lemon juice or vitamin C powder to the purified water.

Iodine flavor
If you are using water purification tablets with iodine you can use iodine neutralizer tablets to neutralize iodine’s flavor.

Chlorine flavor
If you are using water purification tablets with chlorine you can remove the chlorine flavor by allowing the treated water to sit uncovered. That way, the chlorine can evaporate easily


Water purification tablets are easy to carry in your backpack. If you store them properly you can use the tablets for months or even years. You don’t need any special equipment to use the water purification tablets. You don’t need fuel, fire or electricity to use them. So, when you go out into the wilderness we advise you to always take a survival kit with you that include water purification tablets.


It is impossible for water purification tablets to remove sediment or chemical pollutants. If you want to remove this kind of pollution you need more time and a heavier concentration of chemicals. Most of the sediment can be removed when filtering the water before using the tablets.

If you have thyroid problems and you are using iodine tablets it can lead to hypothyroidism and autoimmune thyroiditis. Also, don’t use iodine tablets if you have an iodine allergy or when you are pregnant.
If you don’t store the tablets properly they can lose their effectiveness. In order to get the most out of the water purification tablets and in order to use them safely always read the manufacturer’s information and follow the usage instructions precisely.