Recent extreme climatic events show how vulnerable modern societies are to climate variability. Storms, droughts, heatwaves, fires and floods and their often severe effects on affected populations are documented every day in global media. In this editorial, I outline evidence linking extreme rainfall events, water quality and enteric disease, and ask how this evidence might be applied to better understanding of the impacts of climate change. In New Zealand, a major outbreak of

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... was recently linked to contamination of a local water supply following heavy rainfall. This was the largest recorded outbreak of water-borne disease in New Zealand (and probably for water-borne campylobacteriosis in the world) resulting in an estimated 5500 cases, 45 hospitalisations and three deaths. It triggered a major official inquiry which generated two substantial reports and recommendations for a major overhaul of New Zealand's drinking water system (1). The Inquiry noted that: "Drinking water contamination has the potential to affect extraordinarily large numbers of people and to cause harm at a level which is extremely serious to individuals, communities, businesses, New Zealand's tourism industry and to society as a whole" (1). The Inquiry highlighted the importance of the multi-barrier approach to prevention of water-borne disease, and noted events such as extreme weather that challenge the treatment process are important warning signs of potential contamination. Internationally, research is now filling in the connections between climate change, altered rainfall patterns, rising temperatures and health outcomes (2, 3). While it is difficult to quantify precisely effects of climate change on rainfall, observed climate trends are consistent with the projected effects. The frequency and/or intensity of extreme rainfall events is projected to increase (4). However, attempts to quantify the potential effects of global climate change on enteric disease have so far accounted for effects of increasing temperature, but not rainfall. The main reason for this is the heterogeneity of