The effects of various property-rights regimes on natural resource systems have long been debated among scholars and practitioners. A large number of studies have investigated the relationship between various property-rights regimes and environmental outcomes and show that public, state, and private property regimes are each capable of producing sustainable environmental outcomes. However, the evidence is very diverse. This study examined how the changes in property rights regimes at the local level have impacted on lake degradation using an institutional economics perspective, specifically the property rights approach, by taking Lake Rawapening as the case. Lake Rawapening is a multifunctional semi-natural lake currently degraded where almost 70% of its surface is covered by water hyacinth and experiencing rapid siltation. This research used a case study method. Data and information were collected from in-depth interviews with key informants, government officials and reviews of reports and documents related to Lake Rawapening. Results of the study reveal that the current property rights regime in the lake and its catchment areas associated with social changes was driving local resource users towards greater lake degradation. There were opportunities to build on existing village-level institutions to develop collaborative management systems to help protect the lake ecosystem.