Rationale - what it means and why it is an important measure
The sources of drinking water indicate an exploitation of local aquifers and as well the quality of the drinking water that can influence human health. In some cases, water can be imported that show dependence of different often sources. The drinking water treatment process is depended of source of drinking water as well.
How it is compiled, what data are needed
The percentage of households obtaining water as a primary source from a: (a) piped connection, (b) communal tap, c) vendor or truck, (d) well, stream, lake or dam, (e) others. The percentage of total water consumption for households in a city over several years should be calculated.
Measurements and units
Water from communal tap (% per year) Water from other sources (% per year) Water from piped connection (% per year) Water from vendor or truck (% per year) Water from well, stream, lake or dam (% per year)
Possible temporal and spatial format
trend charts, maps
Reference to methodology resources
UNCHS. Urban Indicators Guidelines: Better Information for Better Cities. EEA Indicator Set.
UNEP, 1999. Global Environment Outlook 2000.
No unified objectives for sources of drinking water; different from city to city.
Targets, benchmarks, reference values
References to examples of application
State of water supply systems in Prague: http://www.ceroi.net/reports/prague/issues/Water/state.htm
Other comments / background
Approximately 60 per cent of large cities in Europe are overexploiting their groundwater resources. Many cities are facing serious shortages of safe water as a result of over-exploitation of resources and pollution. For example, Bangkok's water table has fallen 25 metres since the late 1950s and saltwater has penetrated its wells (WWF 1990).