How to Use Iodine Tablets or Liquid Iodine to Purify or Sterilize Drinking Water InspectAPedia® -
How to treat, purify, or sterilize drinking water in an emergency using iodine tablets or liquid iodine disinfectant
Effectiveness of germicidal iodine tablets for drinking water
Review of Potable Aqua® water purification tablets
Using emergency drinking water germicidal tablets to "make questionable water bacteriologically suitable to drink"
Iodine effectiveness against Giardia lamblia
InspectAPedia offers impartial, unbiased advice without conflicts of interest.
We will block advertisements which we discover or readers inform us are associated with bad business practices,
false-advertising, or junk science. Our contact info is at
InspectAPedia.com/Contact.htm.
Here we explain how to use iodine tablets or liquid iodine as a drinking water disinfectant, and we cite the limitations of this method. This article series outlines methods to purify or sanitize drinking water in an emergency following a disaster such as an earthquake, flood, or hurricane.
For explanation of the types of contaminants found in water and how they are removed in residential water systems, see WATER TESTS, CONTAMINANTS, TREATMENT. See WATER TREATMENT EQUIPMENT CHOICES for details on other water treatment options. See Filters for Drinking Water Purification for a discussion of portable and emergency water filters that are designed to purify drinking water, including portable ceramic water filters, silver ceramic filters, magnetic (bogus) water purifiers, paper and polypropylene water filters, etc.
See DRINKING WATER PURIFICATION for a discussion of various methods used to purify emergency drinking water. A companion article, DRINKING WATER - EMERGENCY SOURCES,describes possible sources of drinking water that may be useful in emergency conditions.
Flood Response Checklist lists key actions you should take after building flooding to minimize mold damage, and includes some safety warnings. Before entering a building that has been affected by a disaster such as fire, earthquake, or flood, See BUILDING ENTRY PROCEDURE AFTER FLOODING for some safety warnings for occupants, building owners, or volunteers who may find themselves indoors in a disaster area and without immediate assistance from rescue workers or other experts.
Guide to Using Iodine, Bleach or Hydrogen Peroxide to Purify Drinking Water
Using Iodine Tablets or Iodine Disinfectant for Water Purification
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.
Iodine tablets: Camping suppliers and other sources also can provide iodine tablets (or other chemical tablets) that can be mixed with a specified quantity of water to produce potable drinking water.
Potable Aqua® iodine water purification tablets (shown at left) are available from camping suppliers and other sources and are an inexpensive means of treating small volumes of emergency drinking water. Potable Aqua® tablets contain the active ingredient Tetraglycine Hydroperiodide 16.7% - equivalent to 8.68% titratable iodine. You can also purchase these tablets online via our bookstore.
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.
Effectiveness of iodine-based water purification tablets:
According to the manufacturer, these germicidal tablets used for "water purification" make questionable water bacteriologically suitable to drink, and the treatment is effective against Giardia Lamblia when used as directed. The product is intended for use when hiking or traveling. Potable Aqua® germicidal tablets have not been shown to inactivate Cryptosporidium cysts.
Watch out: Cryptosporidium cysts might survive a typical chlorine disinfection process (such as at a municipal water treatment plant).
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.
Aquamira™ and Katadyn™ (Micropur) provide portable or field-use water treatment kits using chlorine dioxide.
Katadyn® water purification tablets are sold as Micropur MP1. Quoting from Katadyn's product literature:
The Only EPA Registered Purification Tablets on the Market! And the only disinfection system effective against viruses, bacteria, cryptosporidium, and Giardia. No unpleasant taste. -
Article number: 8014996
Guide to Using Tinctures of Iodine to Disinfect Drinking Water
Tincture of iodine: If you have no iodine tablets but have liquid iodine such as would be used to treat a wound, (typically this is a 2% tincture of iodine) try a teaspoon of iodine in a gallon of water.
Do not use iodine to purify water for certain people:
people who are allergic to iodine - possibly including people allergic to shellfish
people who have a thyroid disorder
people who are taking lithium (a medication)
women over fifty and women who are pregnant (without a doctor's advice)
[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.
Links provided just below continue with details about various methods to disinfect or purify emergency drinking water.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Mark Cramer Inspection Services Mark Cramer, Tampa Florida, Mr. Cramer is a past president of ASHI, the American Society of Home Inspectors and is a Florida home inspector and home inspection educator. (727) 595-4211 mark@BestTampaInspector.com 11/06
Hankey and Brown home inspectors, Eden Prairie, MN, technical review by Roger Hankey, prior chairman, Standards Committee, American Society of Home Inspectors - ASHI. 952 829-0044 - hankeyandbrown.com 11/06
Dr. Omar Amin, of the Tempe AZ
Parasitology Center, corresponded with one of our readers asking about peroxide: "You can use hydrogen peroxide if you want to
but we do not have a track record of percentage dilution".
Dr. Amin has done research for the US military and for the CDC.
Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
Aquamira™ chlorine dioxide water purification kits - see www.aquamira.com/
"Aquamira Water Treatment Drops were introduced to the Outdoor market in 1999 and have been a favorite of top outdoor guides and instructors ever since. Whether you are camping, traveling in a foreign country or faced with a disaster, our goal is to provide you with safe, pure and good tasting drinking water. Our complete line of water treatment products include leading edge purification and filtration technologies developed and tested in the lab and proven in the field. We offer systems and products that will provide water for a single individual or a village and almost anything in between."
Katadyn™, a Swiss corporation provides water filters, desalinization equipment, and their Micropur chlorine dioxide water purification - see www.katadyn.com/usen/
"Katadyn offers a wide variety of water filtration and purification products suitable for any need. This allows outdoor enthusiasts and travelers to take along products for making their own drinking water when preparing their trips."
Arlene Puentes, a licensed home inspector, educator, and building failures researcher in Kingston, NY. 11/29/06
Wilderness Medical Society has advice about boiling water for consumption
Princeton University - www.princeton.edu
"Bacteria in Drinking Water" - "Chlorine," Karen Mancl, water quality specialist, Agricultural Engineering, Ohio State University Extension. Mancl explains factors affecting the effectiveness of chlorine in water as a means to destroy bacteria and other microorganisms. OSU reports as follows:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- http://ohioline.osu.edu/b795/index.html is the front page of this bulletin.
Crystal Clear Supply provides portable ceramic water filter purifiers and portable reverse osmosis water treatment equipment - see http://www.crystalclearsupply.com/category_s/7.htm
"Do Iodine Water Purification Tablets Provide an Effective Barrier against Cryptosporidium parvum?", Starke, Jeffrey A., Bowman, Dwight D., Labare, Michael, Fogarty, Elizabeth A., and others, Military Medicine, 25 October 2001 [possibly a later version of this article appeared in 2005 -DF] http://www.amsus.org/military medicine/milmed.htm
"Drinking Water Safety in Emergencies", University of Minnesota extension, extension.umn.edu/info-u/nutrition/BJ646.html
FDA Warning about drinking hydrogen peroxide: www.truthorfiction.com/rumors/h/hydrogen-peroxide.htm This article cites a 2003 entry in Journal
of Food and Science on using Hy.Perox to sterilize vegetables, referring to E.coli - NOT to Giardia.
www.epa.gov/ogwdw/mdbp/pdf/alter/chapt_2.pdf provides an article on use of disinfectants for water treatment
This patent application for UV light sterilization www.patentstorm.us/patents/6565803.html Lists good references on water
purification for Giardia et als
Giardia exposure limits for drinking water: see www.mass.gov/dep/water/drinking/standards/giardia.htm is the current regulatory exposure limit (your minimum target for
sterilization)
Wikipedia on history of use of hydrogen peroxide: Information on Hydrogen peroxide as a sterilant is in Wikipedia at en.wikipedia.org/wiki/Sterilization_(microbiology) HO2 has been
used for a long time, including by vaporization for sterilizing freeze dryers.
Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
"This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors."
The Pharmaceutical Journal: "This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ... This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended." The Journal of Hospital Infection.: "The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ... The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians."
New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods.
Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..." -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals.
When Technology Fails, Matthew Stein, Chelsea Green Publisher, 2008,493 pages. ISBN-10: 1933392452 ISBN-13: 978-1933392455, "... how to find and sterilize water in the face of utility failure, as well as practical information for dealing with water-quality issues even when the public tap water is still flowing". Mr. Stein's website is www.whentechfails.com/
"Bacteria in Drinking Water" - "Chlorine," Karen Mancl, water quality specialist, Agricultural Engineering, Ohio State University Extension. Mancl explains factors affecting the effectiveness of chlorine in water as a means to destroy bacteria and other microorganisms. OSU reports as follows:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- http://ohioline.osu.edu/b795/index.html is the front page of this bulletin.
CHLORINE IN DRINKING WATER - Does Chlorine in Drinking Water Harm the Septic Tank? - Septic Tank Cleaning Advice
CHLORINE IN SEPTIC WASTEWATER - Septic Tank Maintenance: Chlorine in Septic Systems - Septic Tank Maintenance Advice
Ohio State University article on the concentration of chlorine necessary to act as an effective disinfectant, and the effects of the water's pH and temperature: See http://ohioline.osu.edu/b795/b795_7.html for details.
Water Supply & Drain Piping, Wells, Pumps, Water Supply Equipment
Water pressure tanks - how to diagnose the need for air, how to add air, stop water pump short cycling to avoid damage - water storage water pressure tank safety.
Drinking Water Supply, Contamination Levels, Water Testing Procedures
Water Supply & Drain Piping, Wells, Pumps, Water Supply Equipment
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Crystal Clear Supply provides portable ceramic water filter purifiers and portable reverse osmosis water treatment equipment - see http://www.crystalclearsupply.com/category_s/7.htm
Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..." -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals.
Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
"This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors."
The Pharmaceutical Journal: "This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ... This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended." The Journal of Hospital Infection.: "The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ... The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians."
New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods.
U.S. Army Field Manual 21-10, Field Hygiene and Sanitation, 1988, web search 07/02/2010, original source: http://www.enlisted.info/field-manuals/fm-21-10-field-hygiene-and-sanitation.shtml The purpose of this manual is to assist individual soldiers, unit commanders, leaders and field sanitation teams in preventing disease and environmental injuries. The manual provides information on preventive medicine measures (PMM) to the individual soldier as well as essential information for the unit commander, unit leaders, and the unit field sanitation team on applying unit level PMM.
When Technology Fails, Matthew Stein, Chelsea Green Publisher, 2008,493 pages. ISBN-10: 1933392452 ISBN-13: 978-1933392455, "... how to find and sterilize water in the face of utility failure, as well as practical information for dealing with water-quality issues even when the public tap water is still flowing". Mr. Stein's website is www.whentechfails.com/
Mobile View
Watch out: Cryptosporidium cysts might survive a typical chlorine disinfection process (such as at a municipal water treatment plant).
