As cities continue to grow, far greater pressures will be put on urban water resources. By the year 2015, it is estimated there will be 27 cities with populations above ten million. Of these 27 cities, 22 will be in developing countries -- those least able to provide the needed infrastructure and services for supplying drinking water and sanitation facilities. Six of these cities will have estimated populations at, or exceeding, 20 million people. This congregation of so many people into the relatively small geographic area of a metropolitan setting, with the accompanying demands for water resources and the sheer volume of human and industrial wastes to be disposed of, is an unprecedented occurrence in human existence.
In the cities of the developing world (1996): 50% have piped water to their homes; 25% are supplied by public standpipes, yard taps, protected wells and boreholes with hand pumps; and 25% depend on water vendors and polluted open streams.
The proportion of the population connected to public water supplies varies throughout the countries in the European region as well as between different areas of the same country. In most countries in the European Region, 90% of the urban population have a home connection to drinking-water, but less than 75% of the urban population is connected in a few countries. Logistical difficulties and increased cost mean that rural populations are less likely to receive piped water and have house connections.