This paper examines the implications of adopting catchment scale approaches for the sustainable management of land and water systems. Drawing on the findings of an interdisciplinary study examining how farm management practices impact on the loss of faecal indicator organisms (FIOs) and potential pathogens from land to water, the paper argues that the overwhelming focus on integration at the catchment level may risk ignoring the sub-catchment as an equally appropriate unit of hydrological analysis. Further the paper suggests that many of the management decisions relevant to water quality are made by land occupiers and, therefore, that the identification of relevant socio-spatial units - the 'private spaces' of land holdings - may be as important or more important to the effective management and planning of water resources as catchment-level planning. (C) 2010 Elsevier Ltd. All rights reserved.