The study investigates the performance of lime-treated expansive soil exposed to moisture by assessing the extent of leachability and microstructure alterations. Soil treated with lime in different proportions (4%, 8%) and cured for varied periods (7, 90, 180, and 365 days) were subjected to water percolation for 14 cycles using a modified flexible wall permeameter apparatus. Effluent analysis revealed the significance of the adsorption potential of the clays and the stability of calcium-bearing phases in determining the rate of calcium leachability. The results emphasize the positive effect of moisture percolation in the long-term cured lime-treated samples for enhanced diffusion of calcium and clay mineral ions, augmenting the rate of pozzolanic reactions. Overall, it is noted that the extent of microstructure alterations and leachability in lime-treated soil during the design period primarily depends on its hydraulic conductivity.