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We don’t all have … a tap!We all need tap water, and yet today about 1 billion people in the world do not have access to clean water, roughly ¼ of the world’s population. It has been calculated that in Developing countries, a child under five dies of diarrhea every 3 seconds due to malnutrition and lack of clean drinking water. Indeed 5,000 children and 30,000 adults die each day because they have no access to clean water. Just imagine, that is 2 million children and 11 million people every year! Many more than the deaths caused in the wars our newspapers are full of!

Illustration 1: © Centro Civiltà dell’Acqua.

Have you ever considered how many things you can do with tap water? Could you live without it?Drinking, cooking, washing, cleaning… think of how many things you can do with tap water! What would happen if suddenly no more water came out of your tap? Could you survive? Where would you get your water? You would have to drink, bathe, wash your clothes and cook by obtaining water from a fountain or even from a river or the sea. You could perhaps wash yourself with sea water but you certainly couldn’t drink it to quench your

thirst! The water from your tap or from your fountain is quite special and irreplaceable, not just because it is fresh water, but especially because it is drinking water, clean, safe, rich in mineral salts which are needed to keep our organisms healthy.

Illustration 2-3: © Centro Civiltà dell’AcquaPublic fountains are spread all over the world: a unique

treasure to know and appreciate more.

Houses, schools and offices in the developed countries are all connected to a water supply. But in Developing countries it is very often only the rich who have tap water at home. And the others?In many zones of Africa, Latin America and Asia, the

Love YourTap Water!

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people living on the edges of large citiesdo not have a water supply nor do they have tap water at home. They get their water from publicfountains or wells, normally managed by local cooperatives or citizens councils. In some cases theyare managed by private or intermediary companies which re-sell the water at a much higher price. In many cities like Nairobi (Kenya) or Accra (Ghana) only the rich have a water supply connected to their homes. The poor living in the periphery or in shantytowns have to buy the water from private sellers who distribute it in transportable cisterns right out to the peripheral zones, meaning that there is more than one passage between the water and the family. Indeed, the moreintermediaries there are, the more expensive the final price of the water is. In the end, the poor oftenend up paying much more for water than the rich do, a real paradox, and a great challenge for the development and growth of a number of countries in the southern hemisphere.

Illustrations 4: © COSPE - In some areas of the world water is often carried on shoulders by women.

Water and povertyA United Nations study entitled “Beyond Scarcity: Power, Poverty and the Global Water Crisis”,2006, emphasizes that the lack of global access to water is not so much due to natural factors, such as drought or absence of water, as to the lack of valid water politics. Indeed it is the failure, oreven the total absence of national water politics in Developing countries, together with the spiral of poverty that ensnares so many people, which causes this dramatic situation. One exemplary case is the Republic of Congo, a country where people don’t die because there is no water, but because there is no solid political management. The River Congo which crosses the country is one of the largest rivers in the world, but here there are no water taps for everyone! One more reason for youto love and cherish you tap

Who brings the water to our taps?Water companies manage our drinking water, and to do this, they must rigorously check andpurify the water to be distributed to homes. Sometimes water found in nature contains substancesthat can be harmful to our health if drunk. So water companies must detect these substances through rigorous analysis, and then eliminate them.

Purification, distribution and treatment of waterThe table here below summarizes the 5 main activities carried out by water companies to provide useach day with good tap water, and to manage the “integrated urban water cycle”, or the disposal of used water (grey water and water from the sewage system).

1 COLLECTION - pick up water from water sources and..2 CONVEYANCE – transport water to aqueducts through large pipes.3 PURIFICATION – clean the water and make it safe for drinking (also by adding chlorine).4 DISTRIBUTION – take water to every home by means of very long pipes.5 PURIFICATION OF USED WATER – Once water in the home has been used for washing dishes, or for flushing the toilet, it must be treated before it can be returned to the environment.

Illustration 5: © Centro Civiltà dell’AcquaCleaning water by uplifting: water is pushed upwards from

below. One of the commonest methods of doing this is through a spiral-shaped mechanism.

Cleaning waterBefore water is distributed to our homes, it must be cleaned and this involves a series of operations.The principal ones are: uplift, grilling, sedimentation, filtration and purification. The first process, called uplift, entails the water being pushed upwards from below and one of the commonest

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methods of doing this is by passing it through a spiral-shaped mechanism. This way the water rises up and large impurities like stones and other debris remain below. The second step is grilling. Try to imagine a huge sieve: if we pour water into it, impurities like leaves and soil remain trapped in the sieve. The next step is to place the water in enormous tanks for sedimentation. The other impurities in the water become deposited on the bottom of the tank. But even after sedimentation the water is still not perfectly clean. It is then filtered to get rid of residual impurities and then collected in enormous cisterns. This process is called filtration. Further, if there are other poisonous substances in excess in the water, like arsenic, benzene, lead and mercury, it is brought into contact with specific substances to provoke chemical reactions which purify it. As a final operation, chlorine is added to eliminate bacteria and other organisms that are potentially dangerous forhuman health. This is known as chlorination. Chlorine is necessary even after all these operationsthat have made water perfectly drinkable, because water can become dirty and contaminated again in its journey through the pipes to our homes. Just a small quantity of chlorine prevents this!Uplift and sedimentation are two methods of purification which use the force of gravity. Elementswhose density is greater than that of water are deposited on the bottom because they are unable to compete with the force of gravity.

Illustration 6: © Centro Civiltà dell’Acqua

Sedimentation, filtration and chlorination are the other important processes carried out by water companies to

distribute high quality tap water.

How can we eliminate the taste of chlorine from tap water?This is very easy. Just put a jug of water in the fridge before we put it on the dining table! Chlorine is a gas which evaporates, and at low temperatures, such as those in a fridge it evaporates even more quickly!

How does tap water get to all our homes?Water, like all liquids, doesn’t have a form but rather takes on the form of the recipient that contains it.. If we fill two different containers, joined together by a small tube, with water, the waterreaches the same level in both containers. This is known as the principal of communicating vessels.Aqueducts are based on this principal, made possible by two high towers called “piezometric towers”. Have you ever seen one?

Illustration 7: © Centro Civiltà dell’AcquaPiezometric towers (2), by means of pumping systems (1),

allow the distribution of water in all our homes (3).

Structure no. 1 is the pumping system which pushes water up to the piezometric tower (no. 2), which in turn is connected to tubes that distribute water to our homes (no. 3). Once it has been pushed by structure no. 1 into the piezometric tower, the water falls with the force of gravity and,thanks to the principal of communicating vessels, it runs with great pressure into the tubes until it reaches the taps in our homes.

Depuration of used waterIn developed countries, the water companies are not only responsible for bringing water to our homes but also for treating and purifying already used water to avoid environmental pollution. With so-called grey water and sewage water, a further cleaning process is needed before it can be released into the environment. Depurators are the structures which carry out this important task.

Try solving this mystery: what are Enterococci?Who has heard of the Escherichia Coli? Sadly, they aren’t very nice friends! Enterococci andEscherichia Coli are pathogenic microorganisms of human and animal urine and feces. Aqueducts purify the water for our homes to eliminate

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these enterococci, because they are harmfulfor human health.

Water used by industries is returned to the environment in a degraded or polluted form. Lead,mercury and petrol are just some of the poisons which contaminate rivers and water bearingstrata.Would you drink water containing petrol? Would you eat a mercury sandwich? Obviously not!Thankfully water companies treat these polluting substances for us, but the same can’t be said for other living organisms! Why do we allow fish to swim in lead-contaminated water? And why do we oblige them to eat plankton containing mercury? Toxic substances from industrial use that are poured into seas and rivers first and foremost produce excessive algae growth. If the spillage isextensive, the whole food chain can become seriously endangered, causing the death of numerousspecimens. If they are absorbed by the ground, these toxic substances penetrate very deeply untilthey reach the water bearing strata and not even water meant for drinking is spared! Drinking or washing with water that contains traces of lead, mercury and arsenic leave us open to catchingskin, respiratory and intestinal diseases, and can sometimes even lead to death.

Illustration 8: © Centro Civiltà dell’Acqua

Water courses and water bearing strata can be polluted by over-invasive agricultureIt is the task of water companies to check the levels of water pollution by nitrates, which are very dangerous for humans and especially children. Nitrates are substances that form in nature through the bacterial breakdown of organic material. In agriculture, nitrates are contained in nitrogen fertilizers used to make the land more productive. They are only partially absorbed by the plants,

the rest penetrates into the ground until it reaches and mingles with the water bearing strata. Nitrates are extremely dangerous for the human organism because they transform into nitrite, a substance that joins to hemoglobin thus making our blood less able to transport oxygen to our tissues. FAO and WHO have established that the human body should contain no more than 0 – 0.1mg/kg (body weight) of nitrites. Water companies must control and purify water to guarantee that the quantity of nitrites remains well below these limits.

A “developed” world with an increasing need for water per personDaily water consumption per person varies greatly from country to country and this is due to a number of factors, as we saw in the section “Saving Water” But we also have to consider that our water needs increase significantly with “progress” and economic development! Today, in “developed” countries, a person consumes well above double the amount of the water consumed per person one hundred years ago. Over the span of a century (also taking agricultural and industrial consumption into consideration), water consumption in all “developed” countries has multiplied tenfold almost everywhere! Consumer societies are based on an ever increasing consumption of water resources. To understand the consequences of all this, it is enough to think that in just under 25 years (from 1980 to 2004) the quantity of water potentially available for each human being has almost halved (40%) due to the increase of world population and the daily water requirements per person.

Bottled or tap water?Is bottled water always better than water from the tap? Find out! When travelling or when we are not sure of the quality of the water locally available, it is good practice to drink bottled waterbecause it is safer. However, in many western countries a large number of families prefer to drink bottled water rather than tap water without really knowing why. They are not often aware that thequality of water that comes out of their taps has chemical properties that are similar if not betterthan a host of commercialized water in bottles. Generally speaking the safest water is to drink is tap water because it is subject to more rigorous controls than bottled water. The bottle labels are bright and colorful, saying they come from high mountains and uncontaminated places. But is this true? It doesn’t always match up with the reality. Can you think of any examples?

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Illustrations 9-10: © Altamore (2005)Qualcuno vuol darcela a bere, see references

The dilemma: tap water or bottled water?

The advertising of bottled water Buying water in bottles is surely spurred by the huge investments in advertising made by bottlingcompanies. Each year 120 billion litres of bottled water are consumed in the world and the marketis worth about 80 billion dollars. Not many people realize that aqueduct water is actually subjectby law to more frequent control than bottled water. Have you ever tried comparing the analyses on bottle labels with those of your tap? Which is best?

The costs of bottled waterLast but not least, we should remember that water in plastic bottles produces millions of tons of PET (the name of plastic used for bottles) waste each year. Differentiated waste disposal of plasticcollects and recycles only a small part, the rest finishes in dumps or incinerators which worsen the quality of the air we breathe. One last, but not insignificant cost, concerns the price of bottled

water. Have you ever tried comparing it with tap water? Bottled water costs on average 500 to 1000 times more than tap water! One more reason to find out more about these issues, and, most importantly, learn to appreciate and……… love your tap!

Dossier compiled by:

Water Civilization International Centre, Venice:www.civiltacqua.org

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References

Altamore G. (2005). Qualcuno vuol darcela a bere, Frilli, Milano.

Savenije H.H.G. (2001). Why water is not an ordinary economic good, Value of Water Research Report Series No. 9, UNESCO-IHE, Delft, The Netherlands, www.waterfootprint.org

Seyam, I.M., Hoekstra A.Y. and Savenije H.H.G.(2001). Calculation methods to assess the value of upstream water flows and storage as a function of downstream benefits, Value of Water Research Report Series No. 10, UNESCO-IHE, Delft, The Netherlands, www.waterfootprint.org

UNDP (2006). Human Development Report 2006. Beyond Scarcity: Power, Poverty and the Global Water Crisis, The United Nations Development Programme.

UNEP, Water Quality for Ecosystems and Human Health, United National Environmental Programme, GEMS Water Programme, Ontario, Canada. www.gemswater.org

UNESCO (2009). Water in a Changing World, The United Nations World Water Development Report, n.3, World Water Assessment Program, UNESCO Publishing – earthscan. www.unesco.org/water/wwap/wwdr/wwdr3/pdf/WWDR3_Water_in_a_Changing_World.pdf

Van der Zaag P. and Savenije H.H.G. (2006). Water as an economic good: the value of pricing and the failure of markets, Value of Water Research Report Series No. 19, UNESCO-IHE, Delft, The Netherlands, www.waterfootprint.org

Venice OfficeRegional Bureau for Scienceand Culture in Europe

United NationsEducational, Scientific and

Cultural Organization