Few things are more important to your health and survival
during a long emergency than having water that is safe to drink. Knowing how to
purify water can help you if your regular water supply becomes contaminated or
if you are in a place where clean water is not available. Even if you have
stored clean water to use in an emergency, you may run out before the emergency
situation has ended.
Water purification can greatly reduce your
chance of getting sick from bacteria, viruses, and other living organisms in
the water. You can disinfect water using one of the following methods:
Bring the water to a rolling boil for 1 minute.
If you are at an elevation of
6500 ft (2000 m) or higher,
boil the water for 3 minutes. This is the most effective purification method.
But may be impractical if you need large quantities of water. It also requires
a heat source, which you may not have in some emergency situations. If fuel or
power for your heat source is limited, bringing the water to a boil will
usually disinfect it, even if you cannot boil it for the recommended
Or add 16 drops of household liquid bleach for each gallon
of water, stir, and let it stand for 30 minutes. If the water does not smell
slightly like bleach after 30 minutes, add 16 more drops of bleach and let it
stand for another 15 minutes. You should notice a bleach smell.
use iodine or chlorine purification tablets or drops. You can get these at
stores that sell camping equipment and at some drugstores. Follow the
instructions on the package. Purification tablets are not as effective as
boiling or disinfecting with bleach. But they do kill some types of
Or use water filters that can get rid of some
microorganisms and improve the taste of water. There are many different types
of filters. So be sure that you know what kinds of organisms your filter is
None of the purification methods described above eliminates
heavy metals, salts, chemicals, or radioactive dust or dirt (fallout) from
water. Many of these substances can be removed by distilling water, a more
complicated method of purifying water.
Radioactive fallout can
also be minimized using a homemade filter:
Punch holes in the bottom of a bucket, and
cover the bottom with
1.5 in. (3.8 cm) of gravel.
Cover the gravel with a towel.
Place the bucket over a larger
container, and pour the water into the bucket so that it filters through the
towel and gravel and drains into the container below.
the water by boiling, adding chlorine bleach, or using purification tablets as
Replace the gravel after every 50 qt (47 L) of
How this information was developed to help you make better health decisions.