Here’s a startling figure: 1.5 billion people will live in African cities by 2050, more than double the number today. African cities — including unplanned urban areas and informal settlements — are already facing staggering challenges: poverty, the need for more and better jobs, and a lack of housing and basic infrastructure, all of which will be compounded by rapid urban growth. Yet, in our experience, one of the biggest risks facing cities across Africa is not well understood: water insecurity. Inequitable access to basic water services, loss of natural water systems, unplanned urban expansion, and more frequent and intense droughts and floods will undermine the security, well-being and development prospects of Africa’s urban dwellers — 60% of whom live in slums.