The World Water Week in Stockholm this year focused on one of the increasing challenges for sanitation and water service delivery - urbanization. The global population is now more than half urban and cities are growing at a tremendous rate, especially in the developing world and in the small and medium-sized towns. This rapid urbanization process poses many challenges for those trying to provide services. First and quite simply, the increasing human density corresponds to increasing quantities of waste. This of course leads to environmental degradation, water pollution and a multitude of related health and livelihood impacts. Urbanization exacerbates the need for improved sanitation. Secondly, cities are often experiencing population growth that far exceeds their absorptive capacity in terms of shelter, water, sanitation infrastructure, public health services, employment, education, food supplies and environmental protection - a striking new challenge that has arisen within the span of a lifetime. The service backlog thus gives rise to an increasing number of slums and informal areas lacking adequate sanitation services.

There are a number of recent initiatives moving the focus of urban sanitation to the spotlight. For example, the City Sanitation Strategies in Indonesia that have developed over the last 5 years focusing on city-wide operational which transformed the sector. Increasingly investors such as the World Bank, Gates Foundation, African Water Facilities and European Union are financing urban solutions. The urban environment is challenging, but also leading to innovations in service delivery and financing, like the private entrepreneurs supported through Water & Sanitation for the Urban Poor (WUSP).

In our attempts to come to grips with the scale of the urban challenges there is increasing recognition that the term "urban" hides a complex mix of heterogeneous contexts. There is amazing diversity in the level of service provision within cities, from high income-high water consumption areas connected to sewerage systems, to proper toilets without proper waste management, to nothing at all. Although statistics usually show urban areas as having greater access to sanitation services, this can be misleading. In the case of urban slum dwellers, proximity doesn’t mean access to improved services. At the World Water Week, sector professionals were increasing recognizing that this spatial diversity needs to be taken into account when planning, designing and monitoring for urban sanitation.

In many ways meeting the urban challenge requires a paradigm shift in how we view the urban context and how we design urban sanitation services. The heterogeneous nature of the problem means that the solutions will also have to be heterogeneous. Instead of rolling out a single standard of city-wide services, meeting the needs of ALL city dwellers will mean adapting technology, management and financing structures that are matched to the urban context in which they are living. Matching services to specific contexts and social demographics will mean looking at a multitude of solutions and integrating them along the entire chain of environmental service delivery (including solid waste and drainage). Future city-wide planning may need to allow different standards and options at different levels of the city. One way of doing this is to start looking at the functions that services provide instead of focusing on specific technologies. This will open the door for innovation and critical linkages to complementary services. We need to start thinking out of the box, adapting solutions to specific urban contexts (http://susana.org/lang-en/library?view=ccbktypeitem&type=2&id=1019), and taking action at a variety of levels within the urban context. The urban challenge is also an exciting opportunity for a paradigm shift within the sanitation sector - as long as we remember that this transition requires advocacy and our active engagement at both local and global levels (see my news stream entry from 16th July).