The present study surveyed students from 7 High Education Institutions (HEI) in Portugal aiming at analyzing university students’ perceptions regarding water efficiency. A questionnaire answered by 663 students revealed that they are very aware of the importance of water resources, strongly agreeing that water is essential for the livelihood and health of the environment (73%) and essential for human activities (71%). When asked to rank measure to increase water efficiency, “Reducing leaks and water waste” and “Reduce consumption” were ranked 1st by 39% and 38% of respondents, respectively, while the “Use alternative sources of water” was ranked 4th by 70% of respondents. Students also identified relevant Sustainable Development Goals that are positively affected by adequate water efficiency. The main sources of information identified regarding water efficiency are “Social communication”, “Internet and social media” and “Family background”, revealing the relevance of not only present communication channels but also the importance of intergenerational knowledge passing.