Details of Using Boiling Water to Purify or Sterilize Drinking Water InspectAPedia® -
How to use boiling to treat, purify, or sterilize drinking water in an emergency
How hot, or how long to boil water for drinking purposes
Water heating time requirements at various temperatures in order to sterilize water for drinking
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Here we provide the details of just how long to boil water to sterilize it for drinking purposes. We give water temperatures needed and time durations needed for safe drinking water. This article series outlines methods to purify or sanitize drinking water in an emergency following a disaster such as an earthquake, flood, or hurricane. A companion article, DRINKING WATER - EMERGENCY SOURCES,describes possible sources of drinking water that may be useful in emergency conditions.
If drinking water is of questionable purity, boil the water for at least five minutes, and/or add bleach, and/or distill drinking water before using if a distiller and electrical power or an alternative heat source are available. See information on water treatment under the "Disaster Supplies Kit" section of some public documents.
Boiling water can kill nearly all microorganisms except, as author Matthew Stein points out in When Technology Fails, prions - which are not often present in a water supply. Remember however that boiling water will not reliably remove most chemicals nor will it remove radioactive contamination.
Even if there has been a loss of electrical power, natural or LP gas may be available at some buildings, allowing you to boil water to produce safe drinking water in an emergency. Our page top photo shows a pot of cold water that has just been placed on a natural-gas fired stovetop to begin the boiling procedure. Tip: your water will boil faster and you'll waste less fuel if you keep a top on the container during heating.
Safety Warning: do not enter a building nor attempt to use gas appliances in a building if there is a smell of gas odors or if the gas piping and appliances have been damaged by a storm, earthquake, or other event.
How Long to Heat Water for Drinking
Water Temperature Over
Fahrenheit degrees
Water Temperature Over
Celsius Degrees
Minimum Required Water Heating Time for Purification
160 degF
71. degC
30 minutes
185 degF
85 degC
5 minutes
212 degF
100 degC
1 minute
In most environments, the length of time that water is exposed to temperatures of 185 degF. or higher between the time it reaches 185 degF. and the time that it reaches boiling at 212 degF. is sufficient to kill most organisms and pathogens in the water.
That's why experts have not suggested that you need to boil the water for more than a minute or so. If you are boiling water on an unusually hot powerful heat source, boil it a bit longer to be safe. Typically, experts recommend three minutes of rolling boiling water at sea level altitude.
Links provided just below continue with details about various methods to disinfect or purify emergency drinking water.
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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 treatmen
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.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
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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/
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