o
CO £
£ 3
CO CO
11
551 >
"O o «
o c: c
±; '> cd
c c ra
Z> UJ <
oU.S. GOVERNMENT PRINTING OFFICE: 1 980 — 680-1 A9
United States
Environmental Protection
Agency
WATER	
v-/EPA DON'T DRINK
THE WATER
Until
Have
This ...

-------
During the past few years, increasing numbers
of campers, backpackers, anglers and hunters
have been stricken with waterborne diseases
because they drank water straight from streams,
springs or lakes. Even though the water appears
to be sparkling clean and pure it may contain
microorganisms which cause disease.
One particular organism common in many waters
is Giardia /amb/ia. This parasite has been found
in many wild and domestic animals; therefore, it
can be present in wilderness areas regardless of
whether there are humans in the area.
The organism is transferred between animals and
humans by means of excreted fecal material. If
the infected animal or human defecates in or
near a stream the organisms are then spread
through the water. Beavers are very prevalent in
the transmission of Giardia. Their aquatic habits
insure a steady supply of the parasites to the
water. Since the organisms can survive in water
for at least two months, the problem is not
limited to particular times of the year or sections
of streams.
Drinking water containing a few of these
parasites causes giardiasis, a severe gastro-
intestinal disorder which results in acute
diarrhea, vomiting and loss of appetite. These
conditions can result in serious dehydration of
the body which can be a problem if you are in
the wilderness.
"An ounce of prevention is worth a pound of
cure," and in the case of giardiasis the best
prevention is not to drink naturally occuring
water regardless of how pure it looks. This
means that you must either carry all your own
water or disinfect the water before
drinking it.
Water Disinfection Methods
Of course, carrying your own water is not a
good alternative if you plan to be out for any
length of time, but several methods are available
for making water safe to drink. These are
boiling, homemade disinfectants and commer-
cially prepared disinfectants. The use of
commercially available filters for water purifica-
tion is discouraged since most of the devices do
not filter out particles small enough to eliminate
Giardia, or other smaller organisms.
Boiling kills Giardia, bacteria and viruses.
Research has shown that at sea level, boiling
water for one minute effectively eliminates these
hazards. However, at higher altitudes water boils
at lower temperatures. When you are in the
Rocky Mountains, for instance, longer boiling
times should be observed, (i.e., 15 minutes at
10,000 feet).
Disinfectant
Quantity per
Quart of Water
Waiting Time
Before Drinking
Chlorine Tablets	5 Tablets	30 Minutes*
Household Bleach 4 Drops	30 Minutes
Iodine Tablets	2 Tablets	20 Minutes*
2% Tincture
of Iodine	10 Drops	20 Minutes
Saturated Iodine	Not Recommended
*When using tablet, the waiting time begins after the tablets
are dissolved.
The table below lists the various disinfectants
available and the recommended dosage per quart
of water. The use of saturated iodine (made by
dissolving iodine crystals in water) is not recom-
mended because it does not kill all of the Giardia
organisms in cold water.
Remember, although it may be inviting to dip a
cup of water from a clear, fast flowing mountain
stream, you may regret it later. The best rule to
follow is to disinfect all water when in the back
country.

-------