This thesis examines source separation in the social housing unit Grønnegården in Aalborg. The aim of the thesis is to contribute to the existing research literature in the field of waste management by using a previously unused theoretical perspective: practice theory. Furthermore, the findings will give Hasseris Boligselskab some indications of which efforts should be made to improve the sorting of household waste among the residents in Grønnegården. Previous studies in the field often focuses on distinct aspects of source separation and the field calls for a more holistic understanding of how the various aspects interact and influence each other. By applying a practice theory approach and through qualitative interviews with residents in Grønnegården, the thesis aims to provide a qualitative understanding of source separation in the home. It is found that source separation unfolds in a complex interaction between norms, the materiality of the apartments and the waste itself, the residents’ understanding of how the materiality is handled, their previous experiences and other everyday practices. Pointing forward, Hasseris Boligselskab must focus on installation of sorting systems in the apartments and on information in order to increase the residents’ participation in source separation in Grønnegården.