This post is part of a series of more detailed information on water storage frequently asked questions which includes posts storage containers, alternate sources of water, water purification methods, and more. If you are just getting started in preparedness, we recommend visiting our BabyStep 2: Water page for some basic info on water storage.
Contaminated water can contain parasites as well as microorganisms that cause disease such as dysentery, typhoid fever, salmonella, giardiasis, and hepatitis as well as having a bad odor and taste. You should purify ALL water before using it for drinking, food preparation, or hygiene. NO WATER CAN BE PRESUMED SAFE! Before you begin a purification process, it’s a good idea to strain the water through some sort of filter such as layers of paper towel or a coffee filter to remove any large particles. There are many ways to purify water but none is perfect. Often the best solution is to use a combination of these methods.
Water Purification Methods
Boiling is the most common and safest method of purifying water. Bring water to a rolling boil for 3-5 minutes, keeping in mind that some water will evaporate. Let the water cool before drinking. Boiled water will taste better if you put oxygen back into it by pouring the water back and forth between two clean containers. (or you can add in some of your stored flavorings such as fruit drink powders, kool-aid, hot cocoa, etc.)
According to the American Red Cross, “The only agent used to purify water should be household liquid bleach.” Add 16 drops of bleach per gallon, stir and let stand for 30 minutes. If the water does not have a slight bleach odor, repeat the dosage and let stand another 15 minutes. Do not use scented bleaches, color-safe bleaches, or bleaches with added cleaners. This method is highly recommended as a backup in case fuel is not available for boiling or distilling water.
Distillation involves boiling water and then collecting the vapor that condenses back to water. The condensed vapor will not include salt and other impurities such as heavy metals and most other chemicals that are not removed with boiling or disinfection. To distill, fill a pot halfway with water. Tie a cup to the handle on the pot’s lid so that the cup will hang right-side-up when the lid is upside-down (make sure the cup is not dangling into the water) and boil the water for 20 minutes. The water that drips from the lid into the cup is distilled.
There are two types of water filters, inexpensive travel water bottle filters and gravity carbon filters. A travel water bottle filter is great to throw into your disaster kit, but in cases of extreme contamination you would still want to add in a few drops of iodine or bleach. If you opt for a gravity carbon filter such as the AquaRain or Berkey ones, it MAY be enough purification, but we still recommend to use one of the other methods as well. It can never hurt to be too safe. If you are conserving fuel or on the run, a filter can definitely be a great option and is MUCH better than no purification at all.
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