In this study, the possibility of utilizing waste glass sand (GS) as a sustainable alternative to natural sand (NS) for the production of low-carbon permeable boundary blocks (PBs) was investigated. A modular life cycle assessment approach was employed to evaluate both the environmental and economic impacts of using GS in PBs. The results indicated that substituting landfill-designated waste glass with GS can replace approximately 28396 tons of NS annually in South Korea, thereby significantly reducing resource depletion and landfill demand. PBs incorporating GS achieved up to a 68% reduction in carbon emissions compared with traditional blocks. However, the life-cycle cost analysis showed that the substitution of NS with GS resulted in only 4% cost savings for manufacturers when waste glass disposal costs were excluded. These findings suggest that although GS offers clear environmental advantages, additional tangible economic incentives may be required to encourage its widespread utilization by manufacturers.