As we approach Habitat III in Quito, Ecuador, one of the most essential topics that must be addressed in the New Urban Agenda is urban sanitation.

One in three people in the world lack access to a toilet. The traditional view is that lack of access to toilets is a problem in rural areas. But with rapid urbanization across the developing world, the number of people without access to proper sanitation who live in cities is growing rapidly. This serious urban problem presents a host of new challenges for cities looking to improve sanitation. Since 2011, with Global Communities, I have overseen a series of water and sanitation projects in both rural and urban Ghana. During that time, we’ve identified some of the biggest challenges of urban sanitation:

Lack of planning — In the wealthier neighborhoods of cities that were developed with proper urban planning, providing a toilet can be as simple and low cost as hooking it up to the existing sewer system. But rapid urban expansion in developing countries tends to be in slums which grow haphazardly, with little in the way of planning for the expansion of services, and often little taxation to pay for these services.

Image: Children investigate their community’s newly improved toilets, one of UNOCI’s “quick impact projects” (QIPS) which supported the rehabilitation of schools and toilets in Abidjan. UN Photo/Patricia Esteve.