Most economic development in South Africa has taken place on the dry plateau of the interior following the discovery of minerals. The much smaller wetter parts get most of the run-off and have generally limited possibilities for advantageous use of their water resources. Consequently, it is logical to transfer water between basins with a surplus to ones experiencing shortages. There is a body of opinion that such transfers should be stopped in the interest of the decentralistion policy, but such action is not considered in the national interest. The intricate system of inter-basin transfer from the Komati, the Usutu and the Vaal River to supply the Eastern Transvaal coalfields is described. This system has shown its flexibility during the recent drought. The most important inter-basin transfer scheme is the Tugeia- Vaal Project which is described in broad terms. The advantages of the principle of reserve storage and of co-operation with Escom are dealt with. Possible further projects to augment the Vaal River supplies are mentioned. Other inter-basin transfer schemes implemented by the Department of Water Affairs such as the Orange River Project, the Riviersonderend-Berg River Project and others of lesser importance are dealth with.