Governance and potential of decentralised water reuse in Bengaluru, India

Decentralised wastewater treatment and reuse systems (DWTRS), supported by an enabling governance framework, offer an innovative circular water management solution to the escalating urban water crisis. Bengaluru, one of India’s fast-growing megacities, has emerged as a pioneer in implementing DWTRS at scale, making it a unique case globally. This study examines how the shifts towards decentralisation and circularity have transformed (waste)water policies and practices in Bengaluru, by combining a water reuse value chain conceptualisation with an analysis of the emerging DWTRS governance architecture. The analyses are based on a mixed-methods approach, including policy analysis, stakeholder interviews, quantitative estimation, and site visits. It is estimated that approximately 25% to 60% of the total wastewater generated in the megacity could potentially be reused for various non-potable purposes, both onsite and offsite. The mapping of policy shifts at the city, state, and national levels revealed the key actors and drivers of the water reuse agenda. National policies have driven this shift towards DWTRS in response to growing water contamination and have also set overarching visions and standards that states adopted through top-down processes. Policies of the Karnataka State, combined with judicial intervention and civil society advocacy, led to stricter regulations on wastewater reuse, discharge, and monitoring. Despite a progressive policy vision, DWTRS implementation and scaling is hindered by fragmented regulations, monitoring gaps, and the absence of reuse standards, among other issues. Realising the full potential of DWTRS requires reforms towards a comprehensive multi-level governance framework across the entire reuse value chain that supports a holistic approach to urban water management. These findings contribute to the design of an enabling governance framework for DWTRS and the enhancement of water security in Bengaluru, offering valuable insights for other rapidly urbanising regions with similar water-related challenges.