A critical element for the successful management of wastewater is the active participation of residents in all stages of treatment in order to ensure public acceptance. The primary purpose of this study is to identify and analyze the specific views and attitudes of the inhabitants of Leros Island, Greece, regarding (a) the performance of the wastewater treatment plant (WWTP) operating on Leros Island and (b) their level of awareness on and (c) their willingness to accept a natural wastewater treatment system. This study also emphasizes the significance of a participatory approach to construct sustainable wastewater treatment systems in small communities. Results show an apparent lack of information regarding natural wastewater treatment systems for all respondents, and it turns out that a high level of education does not necessarily mean higher awareness of alternative wastewater treatment methods nor greater acceptance of innovative wastewater treatment systems. Age showed a significant correlation with social acceptance of alternative ways of waste treatment, with people over the age of 56 shown to be most willing to apply a natural wastewater treatment system in remote areas of the Leros island. Environmental awareness policies could contribute to more sustainable community wastewater management.