Most students entering universities in the United States have established views on water resource issues. The purpose of this 25-year study was to measure the impact of science-based education on student opinions of water quality, water quantity, and drinking water issues. A total of 8523 students enrolled in the introductory environmental science class between 1993 and 2017 at the University of Idaho provided opinions to specific water-related statements by taking a repeated measures survey that was administered at the beginning (Week 1) and end (Week 15) of the course. Over 60% of students initially believed (Week 1) that water pollution had gotten worse in the last 25 years; however, by Week 15, 62.8% believed that water pollution had actually decreased. Males were more likely to consider water cleaner, safer, and more plentiful than females. A majority of students initially felt that bottled water was safer than urban tap water (66.1%); however, by the end of the course only 13.4% thought that bottled water was safer. The most important finding of this study was that through a science-based education process, students learned and were willing to change their initial ideas about water issues to align with views that are most accepted by science. Consequently, as long as this and other similar courses at universities across the country are taught from a science-based perspective, they effectively align student opinions with current scientific thought and improve student preparation for making sound decisions about the environment in an increasingly complex world.