Drops of Water 14
Manual for
Saving Water
Water is a diminishing resource!
Water is a vital resource for human life, and yet, today,
there is increasingly less of it on our planet! On Earth
there is a major imbalance in the distribution of fresh
water. We just have to consider that 12% of the world
population consumes 85% of its water. Almost a billion
people have no access to clean drinking water, about 1/4
of the world’s population! It is estimated that by 2005,
due to population increase, this figure will look more like
3 billion people.That is why water has been defined as the
“Blue Gold” of the future.And let’s not forget that 40% of
the world’s population still lives today in terrible hygienic
conditions due to lack of clean water and sanitation.
The number of deaths directly caused by water
transmitted diseases is shocking: almost 30.000 people
(of whom 5.000 are children) die every day because they
have no access to clean, safe water. How much water
do you waste each day without even stopping to think
about it?
The water on Earth seems limitless, but it isn’t!
Time to stop fooling ourselves!
If we hypothesize that on Earth there is a total of 100
litres of water, then the total quantity of fresh water is
equal to only 3 litres (indeed 97 litres is salt water).These
3 litres are mainly composed of ice: only 0.6% is actually
accessible to humans.
Of this percentage again, only a small part is readily
accessible for human usage (lakes and rivers): roughly one
thousandth of the total… little more than a spoonful! It is
important to realize that most of our planet’s fresh water
(3%) is found in the Arctic and the Antarctic, in other
words in glaciers. And it should not be underestimated
that in the future, due to the expanding pollution of
surface and underground water, an ever increasing
quantity of water will no longer be available for human
use as it was in the past.
Illustration 1: © Centro Civiltà dell’Acqua
Total water available on our planet: salt (97%) + fresh (3%) = 100%.
Fresh water 3% (including that of glaciers). Usable fresh
water 0.6% (excluding glaciers). Fresh water used by humans
0.003% (rivers, lakes and water bearing strata).
Let’s learn how to save Blue Gold
If we take a good look at all the foregoing, it is easy to see
why water will become increasingly
precious in years to come, especially in Developing
countries. To make matters worse, desertification,
drought and water scarcity may lead to conflict in the
attempt to take control of this vital resource. That is why
we all really have to make an effort to save water, starting
from our everyday usage!
Drops of Water 14
MANUAL FOR SAVING WATER
What would you be prepared to do to help save water?
Would you melt an iceberg or take the salt out of sea
water?? ... Let’s be realistic! Start saving water today so
that all of us (including future generations) can use it!
Saving water is extremely important! Even working on
our everyday habits, however small, we can achieve great
results… Here are ten pieces of advice that we can put
into practice straight away in order to save an ocean of...
fresh water!
1. Choose to have a shower! It takes roughly 80-100
litres of water to fill a bath. One 4 minute shower uses
up 50 litres on average, so by choosing a shower to a
bath, you can save up to 50 litres of water every time
you wash!
2. Don’t be absent minded! When lathering yourself with
soap, don’t just let the water run away needlessly….a
tap left on can consume up to 10 litres of water per
minute! Why not try this simple calculation: How many
minutes do you spend lathering yourself in a week?
And in a month? How much water, then, could you
save in one year?
3. Turn off the tap when you brush your teeth! Don’t
leave the tap on every time you brush your teeth! If
you do, you can waste up to 20-30 litres of water! If
you turn the tap right off you use only 2 litres!
4. Don’t flush the toilet unnecessarily! Each time you
flush the toilet, 10 – 16 litres of water are used on
average. If you choose the two button flush, you will
waste less water! Alternatively try putting a stone or a
full bottle in the toilet pan: that way less water will be
flushed away when you go to the toilet.
5. Love your tap! Apply a water flow regulator to your
tap instead of the usual filters our taps have. By doing
so, you can reduce water wastage by up to 40%.
6. Reuse the water used to wash fruit and vegetables.
When you wash vegetables, don’t let water run away
needlessly. Rather, fill a recipient and leave them to
soak. Don’t even throw this water away, use it to water
the plants!
7. Plants like drinking... in the evening! Don’t water the
garden at midday in the middle of summer because in
the heat much of the water will just evaporate anyway!
Do it in the evening to keep wastage to a minimum.
8. Collect and use rainwater! Install a cistern in your
garden to collect rainwater. That way you’ll have loads
of water that you can use for plants, flowers and fruit.
Plants don’t like the chlorine in tap water!
9. Do a full load! One load of a dishwater uses 40-50
litres of water; a washing machine can use up to 80120 litres. So only use the dishwater and the washing
machine when they are really full of dirty dishes and
clothes!
10. Cars don’t need chlorine! Every time we wash the
car we use between 100 and 500 litres of water (and in
many countries that water could be used for drinking).
In order to reduce this wastage, use a bucket rather
than a hose and, where possible, use rain water!
Illustration 2: © Centro Civiltà dell’Acqua
Illustration 3: © Centro Civiltà dell’Acqua
Drops of Water 14
Illustration 4: © Centro Civiltà dell’Acqua
Illustration 6: © Centro Civiltà dell’Acqua
Illustration 5: © Centro Civiltà dell’Acqua
Illustration 7: © Centro Civiltà dell’Acqua
Drops of Water 14
GOOD HABITS – A CLOSER LOOK
Collect rain water: a good habit we can all learn!
Just installing a cistern at home for collecting rain water
can save us about 80 litres per day! Here’s an example: If
we use rain water for the toilet flush, which to function
needs filtered and not
necessarily drinkable water, we can save up to 60 litres
of water a day, which otherwise goes right down the
drain! Rain water can also be used to water the garden,
flowers and vegetables. Plants dislike chlorine because it
is a disinfectant, indeed giving a plant tap water to drink
is like giving it poison.
Illustration 8: © Centro Civiltà dell’Acqua
Class Exercise: if we put all these pieces of advice into
practice, how much water could you save each day? And
in a month? And how much could your whole class save
in one year?
And you, how much water do you have?
An African child who lives in a developing country does
not have the same access to water as a child who lives
in the west…. The country which consumes most water
is the USA, with 425 litres of water per day per person.
A Canadian consumes 350 litres per day. What must be
taken into account here of course is the fact the USA
and Canada are water rich countries… The European
average is 165 litres per person a day, although this figure
hides some important differences; in Italy, each inhabitant
consumes around 395 litres of drinkable water per day; in
France, 290. The European countries which consume the
least water are Belgium and Great Britain: approximately
150-160 litres a day. In comparison, for example, an
inhabitant of Angola consumes only 20 litres of water a
day, whereas an Eritrean 8 litres. According to the UN, 40
litres per day is the minimum for survival.
Illustration 9: © FAO Food and Agriculture Organization
of the United Nations, data processed by Centro Civiltà
dell’Acqua - Per capita water consumption in various
countries in the world
How does a water collection and distribution
system work in the home?
Rain water is collected below the ground in a tank which
is reached by means of a drain. Near to this drain there is
a filter to purify the water before it is stored in the tank.
The tank is located below the ground in order to keep
the water at a cool, constant temperature. A switchboard
is set up in the home, a sort of computer which controls
the transport of rain water from the tank to the flush by
means of specially designed pipes.
Illustration 10: © Centro Civiltà dell’Acqua
Rain harvesting and efficient water distribution at home.
Get into the habit of eating fruit and vegetables
which need less water!
The cultivation of maize, millet and barley requires large
amounts of water. There are, however, considerable
differences from one crop to another. For example,
we need approximately 4000-5000 litres of water to
produce one kg of millet. To produce the same amount
of wheat takes about 900-1300 litres of water. So, if we
want to, we can choose in an informed way which crops
to consume and which not….
To promote reduction of water use in agriculture, it is
better to use a drip irrigation system, similar to rain
fall, or to practice hydroponic agriculture. Hydroponic
Drops of Water 14
cultivations are different from others in that they are
not sown in the soil, but rather grown in greenhouses.
Using this method, less water is needed for irrigation.
Salad, tomatoes, peppers and cucumbers are commonly
grown this way.
References
Chapagain, A.K. and Hoekstra, A.Y. (2004). Water
footprints of nations, Value of Water Research Report
Series No. 16, UNESCO-IHE, Delft, the Netherlands.
www.waterfootprint.org/Reports/Report16Vol1.pdf
Even water used for industrial purposes can be
reused!
Industries use huge amounts of water during the
production phases, and those which consume most water
are steelworks, the metal and mechanical industries. A
more forward looking future approach will be to recycle
the water used in these industrial processes.
Chapagain A.K., Hoekstra A.Y. and Savenije H.H.G.
(2005). Saving water through global trade,Value of Water
Research Report Series No. 17, UNESCO-IHE, Delft,The
Netherlands, www.waterfootprint.org
Did you know that most of the water industries
use is for cooling machinery?
In the past, drinkable water was used for these purposes,
but today in many countries, desalinated sea water is used.
After being used for cooling, this water must be purified
and then reused within the productive cycle. Purification
of water for industrial use is done using different
technologies. In membrane filtration, for example, the
water is cleaned by filtering it through subtle membranes
which capture bacteria and impurities.These membranes,
seen through a microscope, look just like sponges.
The most commonly used filtration method is inverse
osmosis. By forcing the osmotic pressure, you cause the
solvent molecules to move from the most to the least
concentrated solution. In this way, the water molecules
are separated from those of other substances.
Dossier compiled by:
Hoekstra, A. Y., Chapagain, A. K., Aldaya, M. M. and
Mekonnen, M. M. (2011).The Water Footprint Assessment
Manual. Setting the Global Standard, Earthscan.
See:
http://www.waterfootprint.org/?page=files/
WaterFootprintAssessmentManual
Lundqvist J., de Fraiture C. and Molden D., (2008). Saving
Water: from Field to Fork. Curbing Losses and Wastage
in the Food Chain, Paper n. 13, Stockholm International
Water Institute. See: http://www.siwi.org/documents/
Resources/Papers/Paper_13_Field_to_Fork.pdf
Mekonnen, M. M. and Hoekstra, A.Y. (2010). The green,
blue and grey water footprint of crops and derived crop
products, vol.1, Value of Water Research Report Series
No. 47, UNESCO-IHE, Delft, the Netherlands.
Rockström, J., Falkenmark, M., Karlberg, L., Hoff, H., Rost,
S., and Gerten, D. (2009). Future water availability for
global food production: the potential of green water for
increasing resilience to global change, Water Resources
Research 45: W00A12, doi:10.1029/2007WR006767.
Water Civilization International Centre,Venice:
www.civiltacqua.org
Venice Office
Regional Bureau for Science
and Culture in Europe
United Nations
Educational, Scientific and
Cultural Organization