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< prev - next > Water for Life - Community water security (Printable PDF)
40 Water for Life
Disinfecting water
Disinfecting water kills germs. If done correctly, disinfection makes water completely
safe to drink. The most effective methods are boiling, solar disinfection, or using
Boiling water
Boiling water for 1 minute makes it safe from germs. Bring water to a rapid, rolling
boil. Once it starts boiling, let it boil for 1 full minute before taking the
pot off to cool. Water needs to boil for 3 minutes to kill germs in high
mountain areas because water boils at a lower temperature
high in the mountains.
Boiling changes the taste of the water and boiled
water takes a long time to cool, so it cannot be
used right away. After boiled water cools
pour it into a bottle and shake it strongly.
This will add air to the water and
improve the taste.
Solar disinfection (SODIS)
Solar disinfection is a very effective way to treat water with only sunlight and a
bottle. Filtering or settling the water first will make it clearer so it will disinfect more
quickly. Solar disinfection works best in countries close to the equator, because the
sun is strongest there. The farther north or south you are, the more time is needed
for disinfection to work. (For more information about SODIS see page 47, Where to get
more information.)
1. Clean a clear plastic or glass bottle or plastic bag.
2. Fill the bottle ¾ full, and shake it for 20 seconds. This will add air
bubbles to the water. Then fill the bottle or bag to the top. The air
bubbles will help to disinfectthe water faster.
3. Place the bottle in an open place where there
is no shade and where people and
animals will not disturb it, like the
roof of a house. Leave the bottle
in the sun for at least 6 hours in
full sun, or 2 days if it is cloudy.
4. Drink directly from the bottle. This
will prevent the possibility of
contamination from hands or other vessels.
Lime or lemon juice
Adding the juice of a lime or lemon to 1 liter
of drinking water will kill most cholera and
other germs as well. This does not make
water completely safe, but may be better
than no treatment in areas where cholera is
a threat. Adding lime or lemon juice to water
before using solar disinfection or the 3 pot
method will improve the effectiveness.
Use 1 lime or lemon for every liter of water.