1. Institute of Public Health and Environmental Engineering, University of Leeds, Leeds LS2 9JT, UK
2. WaterAid, 47-49 Durham Street, London SE11 5JD, UK
3. Department of Public Health, Environmental and Social Determinants of Health, World Health Organization, Avenue Appia 20, Geneva 27 CH-1211, Switzerland
4. Water & Sanitation for the Urban Poor, 7th Floor, Fleet House, 8-12 New Bridge Street, London EC4 V 6AL, UK
5. University of Colorado Boulder; Center for Engineering in Developing Communities, 1440 G Street NW, Washington DC, 20005, USA
6. Division of Data, Research and Policy, UNICEF, New York, USA
7. World Bank, 1818 H Street, NW Washington, DC 20433, USA