Inter-basin water transfer between Johor and Singapore from 1927 to 1941 had a significant impact on Johor’s water supply system. This study aims to assess the consequences of this transfer and provide a contemporary perspective on its implications. Existing research on inter-basin transfers and their impact on water systems between Singapore and Johor is abundant, but there is a notable lack of research specifically addressing Johor’s water system during this time. By examining the historical context and socio-economic dynamics that shaped the inter-basin transfer, this study aims to contribute a unique perspective to the existing body of knowledge. The findings will enhance our understanding of the impacts of inter-basin water transfers and provide valuable insights for water resource management in the region. It also contributes to a comprehensive understanding of the impact of such transfers on contemporary water scarcity issues and provides practical insights for sustainable water resource management globally.