This paper assesses the significance of stabilizing clay soil with calcium lignosulphonate (CLS) and granite sand (GS). Unconfined compressive strength ( (Formula presented.) ) and hydraulic conductivity (K) are taken as performance indicators and the effect of varying dosages of GS (30%, 40%, and 50%) and CLS (0.5%, 1%, 1.5%, and 2%) at different curing periods on (Formula presented.) and K are examined. The best fit regression equations have been proposed to relate (Formula presented.) and K of untreated clay soil and stabilized clay using GS and CLS. The proposed nonlinear regression equations provide details of experimental data and aid in estimating (Formula presented.) and K very efficiently and reliably for targeted geotechnical applications from a sustainable perspective. © 2022 by the authors.