The 6th Mile Reservoir (Twin Summer Storage Tanks) in Rajapalayam has restored through topographical and bathymetric surveys, soil and water quality assessments, seepage reduction, bund strengthening, and desilting to enhance water collection, storage, and supply. CUBE (IIT Madras) prepared the DPR with hydrological analysis and sustainable design strategies. The project addresses Rajapalayam acute water stress by bridging the demand–supply gap, reducing groundwater dependence, and strengthening water security with ecological benefits. Key milestones include scientific surveys, identification of seepage in Tank 2, and actionable rehabilitation planning using innovative methods like drone mapping and bathymetry and catchment integration, the rejuvenation demonstrates a replicable model, highlighting the sustainability of upgrading existing reservoirs over building new infrastructure