Iodine is a chemical water treatment that is one of the oldest water treatment methods out there. It is inexpensive and lightweight, but is not recommended to use over long periods of time and can make your water taste funny. Though iodine does treat for viruses as well as bacteria, it does not treat for cryptosporidium like other chemical treatments such as chlorine dioxide.
Potable Aqua Iodine and Taste Neutralizer Tablets dissolving into water. They take 30 min to effectively purify.
The active ingredient in these tablets is iodine, which treats bacteria and viruses but does not treat Cryptosporidium cysts. It is trustworthy, works on more types of diseases than many filters, and can also treat the water on the threads of your bottle. However, iodine is not recommended by Potable Aqua to use repeatedly over an extended period of time.
Shown here is the disclaimer on the back of the Potable Aqua tablets.
Some people have also shown allergies to iodine. Make sure you are not one of these people before you select this as your treatment method. For a list of the organisms that iodine is effective against, check out Potable Aqua's frequently asked questions and click on the question at the very bottom.
This photo outlines the organisms that these tablets protect against, as of January 2017.
Ease of Use
If you use Potable Aqua Iodine tablets as directed, they are quite simple. Two tablets treat one liter of water, and 2 more taste-neutralizing tablets make the water more desirable to drink after the iodine has incubated.
Even with both bottles, the iodine and taste-neutralizers, this system is small, light (2.27 oz.), and easy to carry.
Time Before Drinking
Once the iodine is dropped into the water, it takes 30 minutes to effectively purify. Then, if you want to neutralize the unappetizing iodine flavor, it takes another 3 minutes for the taste-neutralizers to work on top of the 30. Do not use both types of tablets at the same time since the neutralizing tablets also eliminate the iodine. This is not the most ideal wait time for a backpacker, but since it is not recommended to use iodine repeatedly for an extended period of time, it is a reasonable wait time for a back-up or emergency water treatment system.
Durability / Uses Before Maintenance
There is no maintenance involved in tablets, making them simple and a perfect back-up treatment plan.
Before adding in the taste-neutralizing tablets, the iodine gives the water a medicinal, metallic flavor that isn't bad for the first sip, but becomes nauseating after an entire liter. The neutralizing tablets reduce the medicinal flavor, but leave a faint hint of a metallic taste. In general, the neutralizing tablets work quite well in eliminating the characteristic iodine flavor. Iodine does not filter out particulate like all of the pumps, so if you collect sandy water, you will still be drinking sandy water.
Iodine tablets are recommended for short term (weekend trip) or emergency treatment of water. Do not select iodine as your treatment method for a long thru-hike such as the AT or PCT, because it is not recommended to ingest iodine over an extended period of time.
For only $11 for the iodine and taste neutralizers, this is the cheapest way to get a water treatment system quickly. Since it is not recommended to use over long periods of time, and it doesn't treat for Crytosporidium, spending $3-$5 more on a chlorine dioxide treatment would be a better value.
There are multiple types of iodine for water purification out on the market. Potable Aqua is the most popular brand for the outdoor market.