Developing a state-level water security index to inform sustainable water policy in Peninsular Malaysia

Water security in Peninsular Malaysia remains a critical policy challenge due to fragmented governance, urban expansion, and the uneven distribution of freshwater resources. This study aims to address these challenges by establishing a state-level consolidated water security index (CWSI) that integrates five dimensions, eleven indicators and twenty-nine variables. The CWSI is used to (i) evaluate the current status of water security in eleven states of Peninsular Malaysia and (ii) identify the key risks and challenges associated with water security. Weights for each dimension, indicator, and variable were calculated using the AHP method to ensure methodological rigour. Additionally, normalisation and sensitivity analysis were conducted to ensure cross-state comparability and index robustness. Spatial disparities are clearly evident in the findings. States, such as Terengganu (CWSI = 0.612) and Pahang (CWSI = 0.608), demonstrate strong performance. Meanwhile, Perlis (CWSI = 0.408) and Selangor (CWSI = 0.414) remain vulnerable to persistent water security issues due to dam storage limitations, non-revenue water losses and insufficient treatment capacity. This study suggests that the CWSI be integrated into state-level governance frameworks to guide infrastructure investment, enhance accountability and align performance monitoring with national policies, such as the Water Sector Transformation 2040 (AIR 2040) and the Sustainable Development Goals. By incorporating evidence-based indicators into policy practice, the CWSI provides a tool to strengthen the coherence, transparency and adaptive capacity of Malaysia’s water governance system. Future efforts should prioritise regular index updates to capture temporal variations and address data gaps, thereby supporting more adaptive and evidence-based water security management.