© David Edwards, 2008
PRINCIPLE: LDS leaders have taught us that we may need to treat suspect water in an emergency or a disaster situation to deal with potentially harmful microbes. They have suggested storing agents for water-purification (See, for example, the Church of Jesus Christ of Latter-day Saints, Essentials of Home Production and Storage, p. 11).
PRACTICES: Harmful microbes may be found in water in natural water bodies as well as in some tanks, pipes, etc. If ingested live, these microbes can cause mild to severe or even life-threatening illnesses. You can minimize your risk of water-borne illness by properly treating suspect water. Water from rain, streams, rivers, ponds, lakes and springs can be ingested after it is treated, so long as the water is not also impacted by metals, chemicals or radioactive particles. Here are some of the more common types of water treatment available to the average person.
Pre-Treatment. Pre-treat any water containing plant material, sediment, silt, insects, rust or other visible debris. Let coarse materials in the water settle, strain out debris from the remaining water through a coffee filter, cheesecloth or clean cloth, and collect the water, now ready for treatment.
Boiling. An effective method for killing harmful microbes is to boil water for at least a minute. Downsides to boiling are (1) a heat source and cooking pot are needed; (2) boiling uses a great deal of fuel; (3) use of a heat source requires supervision; (4) heating water to boiling takes much time and cooling it afterward prior to drinking also takes much time, and (5) boiling makes treated water taste “flat”. 
The flatness, however, can be remedied by pouring water back and forth between two containers to aerate it. In contrast to some chemical methods, boiling will kill illness-causing protozoa such as Cryptosporidia and Giardia, found in some natural waters, tanks, pipes, etc.
Filtering Via Gravity. Use a gravity-fed 0.2-micron filter unit with an upper reservoir for suspect water and a lower reservoir for treated water. Most units filter several gallons per day, removing bacteria and protozoa but not viruses (uncommon in U.S. waters). You may also treat chemically.
Treatment Using Regular Bleach. You can treat suspect water by mixing 1/8th teaspoon (or 1/4th tsp if the water is cloudy) unscented 5-6% sodium hypochlorite per gallon of water. Avoid any bleach in which ingredients include chemicals other than sodium hypochlorite and water. Avoid surfactants, perfumes, and other substances. Let the solution stand for 30 minutes or more. This method kills viruses and bacteria but not protozoan cysts.
Treatment Using Water-Purification Tablets. Only one type of water-purification tablet is EPA registered as a purifier, effective against protozoa, viruses and bacteria: Katadyn’s Micropur MP1. For cold, dirty water, treatment time is four hours. For warm, clear water, treatment may occur in 15 minutes (see www.equipped.org/watrfood.htm). (For info only: we do not endorse any product.)
Notes: Up to 8% of people respond adversely to iodine, once widely used to treat water. Hydrogen peroxide is hazardous, not recommended for home use, at high concentrations (>8%); at lower ones, it fails to treat water well.
Photo of protozoan Giardia lamblia retrieved 13 July 2008 from www.nih.gov/news/research_matters/october2007/images/parasite_l.gif
Photo of pot and boiling retrieved 13 July 2008 from http://ga.water.usgs.gov/edu/pictures/wcsublimationpot.jpg
Picture of pouring water back and forth retrieved 13 July 2008 from www.epa.gov/OGWDW/faq/images/emerg_image3.jpg
Picture of bleach bottle retrieved 21 June 2008 from http://emergency.cdc.gov/disasters/floods/pdf/flyer-keepfoodsafe.pdf
Additional info: www.ext.colostate.edu/pubs/natres/06704.html and www.ianrpubs.unl.edu/epublic/live/g1494/build/g1494.pdf
Next week, more on treating suspect water.
