Municipal solid waste (MSW) landfills are particularly complex engineering structures and according to Eurocode 7 and environmental hazards, belong to the third geotechnical category. Technical reclamation work usually focuses on ensuring the overall geotechnical safety of contaminating structures, by sealing the top of the landfill, using cohesive mineral soil, or using synthetic materials. Owing to legal requirements, specific locations, or challenging soil and water conditions, reclamation methods differ around the world. The paper presents a comprehensive analysis of two reclamation systems for MSW landfills used in Poland and the Czech Republic to determine the impact of selected landfill reclamation methods and capping systems on the environment. The processes in landfills differentiate the object not only in terms of quantity but also in terms of chemical composition. Based on long-term monitoring, the samples were characterized to check their basic physicochemical parameters and variability over time. To verify the effectiveness of landfill capping systems, analysis of the level of heavy metal contamination of leachate and analysis of groundwater quality in the vicinity of the landfill were carried out. The results of this study showed that the appropriate selection of technical reclamation methods is crucial and has a significant impact on the processes of a closed landfill and on the environment itself.