Page 520 - Shaping smarter and more sustainable cities - Striving for sustainable development goals

3.5 Water availability and quality

Urban water sources are very diverse. They include rivers, lakes, reservoirs, groundwater,
desalination plants or a mixture of these sources. In many metropolitan areas, however, due to the
growth of urbanization, the supply may extend far beyond the city's watershed. Such large cities
rely heavily on a regional scale supply and distribution system. This is further complicated as
freshwater is unevenly distributed over space and time, which places major planning and
management challenges to the water sector. Approximately 700 million people in 43 countries are
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currently suffering from water stress and scarcity , with over 1 billion people without access to
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clean water , and over 2.6 million lacking adequate sanitation facilities .
In developing countries, poor water and sanitation facilities are the source of health problems for
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almost half of the population, and can be linked to 80% of diseases . Urban pollution has also
gradually led to the deterioration in water quality. Only 10% of the world's cities currently have
water treatment facilities, and 90% of untreated wastewater in developing countries is discharged
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into rivers , further decreasing the availability of clean water resources for urban inhabitants.
Therefore, providing a clean supply of water is considered to be both challenging and expensive.

Considering existing gaps in water demand and distribution, climate change impacts and poor water
management magnify the vulnerability of countries that are experiencing water stress and weak
water infrastructure. Water scarcity is not only a threat to human and economic development, but
it may become a source of political instability in years to come. Illustrating the magnitude of water‐
related vulnerability at the global level, Figure 4 provides a baseline of water stress and projected
changes by 2025. Climate change‐related stressors on the urban water management are explained
below.

510 ITU‐T's Technical Reports and Specifications