Safe Water in
Emergencies
Byron J. Wilson and H. Smith Broadbent,
“Safe Water in Emergencies,” Ensign, Feb. 1986, 70
Obtaining good-tasting, contamination-free water is ordinarily not a
problem. But in times of emergency, on outdoor trips, or when traveling in
under-developed areas, having access to a source of drinkable water is a
matter of first priority. The bacteria, viruses, and parasites in
contaminated water can create many kinds of health problems.
When the purity of water is questionable, use the following steps to
make it safe to drink:
1. Clarify cloudy water by adding a small amount of powdered
kitchen alum—about 1/4 level teaspoon per gallon. Larger amounts are
not more effective! Crystals take much longer to dissolve than does
powder. The alum reacts with the water, producing a precipitate which
slowly settles and absorbs impurities. After settling is complete (fifteen
minutes to an hour or two, depending on the water) pour the water into
another container, being careful not to stir up the sludge at the bottom.
Discard the sludge, and the water is ready to be disinfected. If you
don’t have any alum, filter the water through a tightly woven cloth.
Clarification is important; clear water can be purified using less
chlorine or iodine than you need for cloudy water. When the water is
clear, you are ready to disinfect it.
2. Disinfect the water by one of the following methods:
Boiling. Boil the water at least three minutes after it has come
to a rolling boil. This is the best method if fuel is available. (At
elevations of ten thousand feet or more, water should be boiled for
fifteen minutes because it boils at a lower temperature at higher
elevations.)
Chlorine. Add five drops of chlorine bleach solution (4 to 6
percent hypochlorite solutions such as Clorox or Purex work well) per
quart of water. Let the water stand thirty minutes. If there is no
residual odor of chlorine, repeat the treatment until a definite chlorine
odor remains. A small plastic bottle of bleach solution will purify a lot
of water, but the chlorine solution deteriorates with time, so replace
your bottle on a yearly basis. Halazone tablets release chlorine slowly,
but they are expensive, have a relatively short shelf life, and are less
effective.
Iodine. Add eight drops of a 2 percent tincture of iodine
solution (obtainable at most pharmacies) to a quart of water, and let
stand about thirty minutes.
Best of all, you can make your own iodine solution with about five
grams of iodine crystals (also obtainable at most pharmacies) in a
two-ounce glass prescription bottle. (Plastic bottles darken after a
while.) Cover the crystals with a small amount of water to retard
sublimation. Freezing this mixture should not crack the container.
When you are ready to use the iodine solution, fill the two-ounce
prescription bottle with water, put the cap on, and shake the bottle for
several minutes. Let the heavy crystals settle, then carefully pour out
approximately three tablespoons (almost all the solution) into a gallon of
clear water. Stir, and let the water stand for approximately thirty
minutes. If the water is ice cold, let it stand for an hour. If you find
the taste of iodine objectionable, use half the amount of iodine solution,
and let the treated water stand twice as long. (Most people find the
iodine taste less objectionable than that of chlorine in chlorinated
water.) Use only the iodine solution; leave the crystals in the bottle.
You can use the crystals up to about three hundred times before they
completely dissolve.
Keep the solid iodine away from children. Do not touch the crystals!
Solid iodine is very irritating to the skin and will stain most things
it touches, although alcohol will dissolve it readily. The violet vapors
are very corrosive!
The iodine crystal method of water purification is inexpensive, and
actually more effective than chlorination. As solid iodine has an
indefinite shelf life, one bottle should last a lifetime for emergency
use.
As a reminder, put labels on the alum and iodine containers:
Kitchen Alum
1/4 tsp./gal. cloudy water
Let stand until clear
Iodine Solution
Approximately 3 Tbsp./gal.
clear water
Let stand approximately thirty minutes.
We have used the alum clarification and iodine disinfection methods
successfully on many backpacking and canoeing trips. Only persons who are
sensitive to iodine or who are being treated for hyperthyroidism might
suffer any ill effects from this method; no other adverse physiological
symptoms have been noted in tests using sample groups. Byron
J. Wilson and H. Smith
Broadbent, Provo, Utah
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