nding the disadvantages, a number of developing world urban areas were and still are encouraged by developed world consultants, with the tacit support of donor organisations, to utilise large-scale centralised wastewater systems. This is despite the use of precious water to transport the wastes, making it unsuitable in the long term for regions with water scarcity. In many places this has already led to an overexploitation of limited renewable water resources (Werner et al., 2004). Rural water requires infrastructure systems different from the urban ones outlined above. Although some rural supplies come from surface sources, usually wells or boreholes are drilled and installed to access groundwater. Institutionally the governance and financing arrangements differ considerably from urban areas, and often the same level of service is not available. To sum up this section, although the majority of the world's population, now and in the future, are likely to live in urban conurbations, there are INFRASTRUCTURE TO 2030: TELECOM, LAND TRANSPORT, WATER AND ELECTRICITY - ISBN 92-64-02398-4 © OECD 2006 5. THE IMPACTS OF CHANGE ON THE LONG-TERM FUTURE DEMAND FOR WATER SECTOR INFRASTRUCTURE important water needs in rural areas that also need to be considered. This requires consideration of infrastructure for: all sources of abstraction (surface or groundwater) and storage; water treatment processes; transmission and distribution; wastewater collection and conveyance systems; and wastewater treatment and residuals management. Geographic scope Globally the main actors may be nation states, although increasingly multinational organisations seem capable of operating semi-autonomously. Nevertheless, here the most successful countries worldwide will be considered in terms of the future needs for water infrastructure. These are the 30 OECD countries plus China, India, Brazil and Russia. Mention will also be made of states in Central and Eastern Europe and Central Asia (the former Soviet Bloc) as well as some mention of sub-Saharan