Leachate is defined as the liquid that drains from the landfill. The paper presents the physico-chemical, bacteriological and heavy metal testing results carried out for leachate, surface and sub-surface water samples collected from municipal solid waste landfill and different water sources in Solan to find out the effect of leachate percolation on groundwater quality. Physico-chemical parameters analysed were, pH, Total Dissolve Solid (TDS), sulphate, turbidity, Electrical Conductivity (EC) while biological parameters tested were Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Most Probable Number (MPN) test and ammonical nitrogen. Testing for heavy metals (Pb, Zn, Cr, Ni, Fe) were carried out and have been reported. The results reveal that the leachate from the unlined landfill may have a significant impact on the groundwater resource (often used as drinking source) particularly because of the toxic nature of the leachate coupled with the soil characteristics which is permeable in nature.