Point-of-use water treatment (PoUWT), such as boiling or chlorine disinfection, has long been recommended in emergencies. While there is increasing evidence that these and other PoUWT options improve household water microbiological quality and reduce diarrhoeal disease in the development context, it is unknown whether these results are generalizable to emergencies. The authors conducted a literature review and survey of implementers, and found that PoUWT was effective in small-scale, non-acute, high diarrhoeal disease-risk emergencies when training and materials were provided to recipients, adequate stocks were maintained, and chlorine dosage was appropriate. There was little documented effectiveness in acute emergencies, with untested products, or during large-scale distributions without training. Results were incorporated into the Sphere Revision, which recommends selecting culturally acceptable PoUWT options, providing adequate products and training to recipients, pre-placing PoUWT products in emergency-prone areas, and using locally available products if continued use in the postemergency phase is desired.