This experiment traces the risk of diarrhoea among children 1-4 years of age, in Jakarta, Indonesia’s slums. In most developing country slums, access to piped water is all communities have, safe water is unavailable – and purchasing bottled water is prohibitively expensive. In this case, drinking water from community-scale decentralized water treatment and refill kiosks was sold to find significant reductions in rate of diarrhoea per thousand children. Read the report here.