Polymers have many applications in the construction industry. Geopolymers are inorganic polymers adopted for various construction works due to their noteworthy properties. Contrastingly, geopolymers are prepared from alumino-silicate-sourced materials through an alkaline activation process which contains pollutants. The contaminants from the geopolymer may move through the pores in the soil. Therefore, geopolymers may contaminate groundwater while being utilized for ground modification. This study deals with the geo-environmental effectiveness of the implementation of geopolymers synthesized from industrial wastes and by-products for road subgrade construction. Various geotechnical properties like the unconfined compressive strength and California bearing ratio are studied. Moreover, the chemical properties of geopolymers, i.e., their pH, leaching effect, and contamination ability of groundwater, have been studied. The geopolymer-modified soil showed improved geotechnical properties. The contaminant concentrations in groundwater due to polymeric material are within the limits of drinking water quality as prescribed by the WHO. Geopolymers have been proven to have potential as alternatives to conventional subgrade materials with no contamination effect.