In this paper we review the effects of the provision of artificial sources of water on native flora and fauna in arid and semi-arid zones, with emphasis on Australia but drawing on information from other countries where possible. The effects of artificial sources of water are profound and are a rarely-cited aspect of change in arid and semi-arid zone rangelands. Direct effects of artificial sources of water include: (1) the development of wetlands that support native plants and animals; (2) the expansion of geographic range and increased abundance of native animals which need to drink regularly; and (3) the possible expansion of breeding ranges of invertebrates that require water for some stage of their life cycle. The major indirect effects of artificial sources of water are as a source of drinking water for domestic stock, and native and feral mammalian herbivores, and so they provide a focus for grazing. Keywords: bore, dam, grazing, water, piosphere, rangeland, arid zone, biodiversity.