How to Make Water Safe to Drink

(Three methods)
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METHOD

PROCEDURE

Heat

Boil water for 1 minute. At altitudes 2000 meters (6,500 feet) or more above sea level, boil water for 3 minutes. Note: This method makes water safe for drinking, but it should not be considered sterile for other purposes (bacterial spores will survive boiling).
Filtration
 Most commercially-available water filters have pore sizes of 0.1 - 0.4 mm. These will effectively remove bacteria and parasites, but may not remove viruses. If a filter is designated as a water "purifier" by the EPA, it is purportedly able to remove 99.99% of viruses. Note: Filters will eventually clog with use.
Chemical treatment

Potable Aqua® or Globaline®

To 1 liter of water: add 1/2 tablet and wait 45 minutes; or
Add 1 tablet and wait for 15 mins.
 

2% tincture of iodine

To 1 liter of water: add 5 drops and wait 45 minutes; or
Add 10 drops and wait for 15 minutes.
 

5% sodium hypochlorite
(Household bleach)

To 1 liter of water: add 2 drops and wait 45 minutes; or
Add 4 drops and wait for 15 minutes.
 

AquaClear® or Chlor-floc®

To 1 liter of water: add 1 tablet and wait 15 minutes.
 

Disadvantages of chlorine and iodine treatments:

    1) imparts a taste/odor to water (which can be removed by charcoal filters).
    2) is not effective against all water-borne pathogens (e.g., Cryptosporidium). Chlorine dioxide tablets are effective against all water-borne pathogens.
    3) may not be effective if the water is visibly contaminated or cloudy
    4) continuous, long-term consumption of iodine may have adverse effects

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