One of the primary targets of MDG 7, dealing with issues of environmental sustainability, is to halve by 2015 (from 1990 levels) the proportion of the population without sustainable access to safe drinking water and basic sanitation. It is undoubtedly difficult to summarise a complex target such as access to water or safety of water source in a single quantifiable indicator. However, in our opinion, the indicators used to estimate how much of the population has 'access' to 'safe' drinking water leave out some important elements that should be taken into account when determining whether the goals have been met. In addition, the authors propose a modification to Bradley's classification of water-related illness to include a category for waterborne diseases of a non-infectious aetiology.