1. The Water Institute, Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, 135 Dauer Drive, CB #7431, Chapel Hill, North Carolina 27599, USA
2. Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, 3101 McGavran-Greenberg Hall, Chapel Hill, North Carolina 27599, USA
3. ICF, 2635 Meridian Pkwy Suite 200, Durham, North Carolina, 27713, USA
4. The Water Project, PO Box 3353, Concord, New Hampshire, 03302, USA
5. Regional Office for the Middle East and North Africa, UNICEF, Amman, Jordan
6. School of Civil Engineering, University of Leeds, Leeds, UK