Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
Iodine or iodine tablets to purify drinking water: Here we explain how to use iodine tablets or liquid iodine as a drinking water disinfectant, and we cite the limitations of this method.
Green links show where you are. © Copyright 2015 InspectApedia.com, All Rights Reserved.
This article series outlines methods to purify or sanitize drinking water in an emergency following a disaster such as an earthquake, flood, or hurricane.
Iodine and bleach (chlorine or sodium hypochlorite) are the two common ways to sterilize water chemically to address bacterial contaminants. Iodine tablets have been shown to be effective against Giardia muris but iodine tablets are not effective against Cryptosporidium species.
[Click to enlarge any image]
How to use water purification tablets:
Paraphrasing the Potable Aqua® instructions: Two tablets are added to a quart of water (or to 1 liter of water) to be treated. The water plus tablets is left in a loosely-capped bottle or similar container, loose enough to allow some leakage. Allow this combination to stand for five minutes, then shake the container to moisten the threads on the container and its cap. Then tighten the cap and allow the water plus tablets to sit for 30 minutes before drinking.
For this reason some municipalities where Cryptosporidium cysts are a concern add a water treatment step using chlorine dioxide. Others may use a combination of UV light and chlorine in the water treatment procedure. This treatment is also available to hikers, travelers, and for emergency water supply use.
Katadyn® water purification tablets are sold as Micropur MP1. Quoting from Katadyn's product literature:
See FILTERS for DRINKING WATER PURIFICATION for some alternative approaches to water purification that can handle cryptosporidium cysts.
Guide to Using Tinctures of Iodine to Disinfect Drinking Water
Also see Wait Time & Water Temperature When Adding a Disinfectant - Before Drinking the Water where we provide more details about how to use iodine as a disinfectant.
[OPINION] In an emergency if you have nothing else, no way to boil water, no ceramic filter, but you have iodine, use it. But beware that iodine is not fully effective as a water sterilization method and be sure to see the allergic reaction warnings just above.
Using Lugol's Solution for Water Disinfection?
Reader question: I looked at the article about water sterilization from the link that you sent me and I saw no mention of Lugol's iodine as a sterilizing agent. Am I missing an article? I did see the post about using chlorine to kill Giardia cysts (GIARDIA in DRINKING WATER) where you cite:
Is that 10 parts of chlorine to one part of Water? Is that the dilution of chlorine that one woul buy in a container of Chlorox? Thanks - G.B. / S.R. 5/30/2013
Watch out: The Manci citation specifies 10 milligrams of chlorine per liter of water: That is nowhere near a 10:1 ratio. Confusion about proper dilutions of disinfectants can lead to dangerous drinking water.
Furthermore, even with proper levels of chlorine disinfectant in water and proper contact time and proper water pH adjustment, disinfecting water does not remove other contaminants. See WATER DISINFECTION LIMITATIONS.
Lugol's Solution or Lugol's Iodine I2KI
Indeed chlorine (bleach), iodine, and permanganate all have been widely used in water treatment and disinfection systems. We have written about iodine as a water disinfectant and I've used various formulations including Lugol's iodine in the lab as a stain, but I've not written not specifically iodine mixed with potassium iodide - Lugol's solution - as a water disinfectant. (Synonymns I2KI (iodine-potassium iodide); Markodine, Strong solution (Systemic); and Aqueous Iodine Solution BCP).
I've read that while there is a historic use as a water disinfectant including following Chernobyl (where it had a second purpose) the mix can also be toxic if drunk or ingested at concentrations of 2% & above. The Wikipedia article adds "The lethal dose of free iodine for an adult human of 2 to 3 grams (2000-3000 mg) free iodine represents 40 to 60 mL (less than 2 fluid ounces) of 5% Lugol's solution. I'll add these notes to our iodine discussion found at along with some useful citations  about iodine as a disinfectant in articles citing the preparation and use of Lugol's solution.
Because there can be health problems from unsupervised consumpation of iodine, and lacking expert sources that argue otherwise, I am not competent to recommend regular use of Lugol's solution as a general purpose water disinfectant in any of the forms discussed. Here is what Backer & Hollowell say about using iodine (but not specifically Lugol's solution) to disinfect water:
Continue reading at SOLAR WATER DISINFECTIONor select a topic from the More Reading links shown below.
Suggested citation for this web page
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Questions & answers or comments about using iodine or iodine tablets to purify drinking water.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References