<p>When active workings are close to a water-logged area, heavy inrush or seepage of water can occur, causing loss of life and resources. As a preventive measure, a water barrier pillar (WBP) of suitable width is left unmined between the workings throughout the mine life. The optimal size of the WBP is essential for ensuring safety in underground mines. The WBP design employs empirical, analytical, physical, and numerical methodologies. Empirical approaches exhibit limitations in predicting seepage effects, whereas physical and analytical methods are often time-consuming and may fail to represent field conditions accurately. Numerical methods can comprehensively analyse WBP behaviour across different stress-seepage conditions. In India, empirical methods are typically used to design WBPs. However, more research is required to design WBPs to sustain static and dynamic stress-seepage conditions. Therefore, a rational approach to designing the WBP must be considered. This work critically reviews best practices and governing parameters for safe WBP design and their failure mechanisms, using various design methodologies to analyse WBP behaviour. Current research and field experiences of WBP design are reviewed by highlighting their strengths and weaknesses. Hydro-mechanical coupling and case studies are examined to identify causes of failure, emphasising the need for more effective design strategies to prevent mine inundations.</p>