How To Purify Water

It will be necessary in the event of a disaster to know how to purify water. Your tap water will not flow without electricity, and there may be none after the disaster.

There are many sources of water in your home, which we covered here. But what sources could there be outside of your home?

Water Sources

• Do you have a well? If you do, you will need an alternate source of power to operate the well pump.
• mountain streams
• lakes or reservoirs
• springs
• swimming pools and hot tubs
• old capped wells
• rainwater - Rainwater can be collected in some areas but is illegal in others (like Colorado). But don't assume that you can drink it as is - remember there are birds and insects living on the roof and their feces end up in the tank. It can be, however, a good source of water.

Always assume that any water other
than from a deep well is contaminated.

How to Purify Water

There are several methods to purify water. It is an old wives' tale that beds of sand and gravel purify water. The space between grains of sand is more than enough to let microscopic giardia lamblia parasites pass between them. Trust me - you do NOT want giardia!

Giardia and Cryptosporidiuum are two waterborne diseases that are often found in swimming pools and hot tubs as well as in rural settings. They are spread by human and animal feces and are hard to destroy.

Chlorine Dioxide Tablets

Chlorine dioxide is a well established disinfectant and is free of iodine and active chlorine. (Although chlorine dioxide has the word chlorine in its name, the two forms of chlorine have completely different chemical structures. The oxygen radically changes the molecule and creates completely different chemical behaviors and by-products.) They have a shelf life of 3-4 years, depending on the brand.

Manufactured by Portable Aqua, Katadyn Micropur, and Aquamira, these tablets kill bacteria, viruses and cysts, including Giardia and Cryptosporidium.

Iodine Tablets

One tablet added to a quart of water releases 8 ppm (parts per million) of iodine. Two tablets are used for cloudy water. Wait 15 minutes after adding tablets, 30 minutes if the water is cold. Iodine tables are not effective against Giardia and Cryptosporidium and can have adverse health effects on some people.

Chlorox or Chlorine Bleach

Common household Clorox or chlorine bleach may be used to disinfect water in these amounts:

You should be able to smell a slight odor of chlorine after the water sits for about 15 minutes. If not, add more Chlorox. Chlorinated bleach loses its strength with time. After one year on the shelf, it will have lost 50T of its strength, so double the dose. Do not use scented bleach or bleach with additives.

WARNING: Chlorine or iodine will not reliably kill Giardia and Cryptosporidium. At colder temperatures, doubling or tripling the wait time will improve your chances. Boiling or chlorine dioxide tablets and good water filters are more reliable.

WARNING: Pregnant or nursing women or persons with thyroid problems should not drink water disinfected with iodine.

Solar Water Disinfection (SODIS)

Pour clean water into Pet bottles and expose to sunlight for a minimum of six hours if the sky is bright or up to 50% cloudy. If the sky is 50 to 100 percent overcast, the container needs to be exposed to the sun for two consecutive days. Plastic bottles made from PET (PolyEthylene Terephtalate) or clear glass bottles are preferred. Avoid the use of bottles made of PVC (PollyVinylchloride).

This method uses solar radiation and heat to destroy pathogenic microorganisms, which cause waterborne diseases. PVC bottles contain UV stabilizers, which blocks the sun's radiation. (PVC bottles often have a slight bluish color.)

Backpack Filters

Since there are many poor quality filters on the market, make sure the filter you purchase will filter protozoa, bacteria and viruses down to 0.5 microns. It should also be certified to EPA Guide Standards for microbiological purifiers against bacteria, cysts and viruses.

Katadyn Hiker Pro Microfilter is a very reputable brand. It is small, light (11 oz.) and never needs cleaning. The output is up to one quart (one liter) per minute with a cartridge service life of 200 gallons, depending on the water quality or when the filter becomes hard to pump. It also uses an anti-clog technology which is a great feature.

The Katadyn Hiker Microfilter meets industry standards for reduction of Klebsiella terrigena
bacteria (99.9999%) and protozoan cysts like Giardia and Cryptosproidium (99.9%), but it does not eliminate viruses (use with Micropur Tablets or Potable Aqua tablets).

Buy the best you can afford - this is not the item you should economize. Learn to use the filters - they take a little practice. Don't forget to store extra replacement filters.

Gravity Flow Filters

They are simple to use and can treat thousands of gallons of water without electricity, without plumbing, and without pressure or chemical pretreatments. The AquaRain Gravity Flow Filter uses patented ceramic technology and positively removes dangerous living organisms and harmful bacteria from your drinking water naturally, using microfiltration and gravity.

Gravity flow filters have been laboratory tested and will remove dangerous organisms such as protozoan cysts (Cryptosporidium, Giardia lamblia) and microscopic bacteria (E. coli, Salmonella typhimurium, etc.)

For a permanent residence, a good gravity flow filter is superior and much more convenient. They require no chemicals and since they operate by gravity, no pumping is required. They purify your water while you are free to do other things and they have a one to two gallon storage reservoir. There is a convenient tap on the bottom reservoir.

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