Purpose: Higher education institutions have a significant impact in preparing future generations for the creation of a sustainable society. By formulating appropriate curricula, the university can shape student personality with sustainability concerns. This study aims to present the results of a teaching approach on environmental sustainability using the photovoice methodology. A guided visit to the sewage treatment plant of A Coruña was included as a teaching activity in the "Microbiology and Parasitology" classes of the podiatry degree at University of A Coruña. The teaching objectives were to reinforce contents through observation and to introduce citizen awareness on sustainability and responsible water use in a cross-sectional manner. Design/methodology/approach: In this case study, different steps of photovoice as a qualitative participatory action methodology were developed. A total of 43 university students willingly participated with their photographs. Qualitative data were collected from the students' photovoice visit reports and a subsequent discussion group. Thematic content analysis was performed manually. Findings: This study explored the impact of an environmental sustainability teaching activity on the university student community. Six main categories emerged from the qualitative analysis: savings/waste of water, misuse of the water closet, disposing of used oil, solid waste/trash, reuse of clean water and reuse/reduction of the use of plastics. The cross-sectional findings on the needs of education and awareness of sustainability in the community and companies are presented. Originality/value: The findings provide evidence of the ability of photovoice method as a pedagogical tool to promote reflection and change in the university community and to introduce sustainability cross-sectional content in green campus curricula. This photovoice experiment is simple and feasible to implement and has a very low economic cost, as long as there are qualified educators.