A first-year graduate student of filming at the Academy of Dramatic Arts in Zagreb, had an idea to make a video story about water for his student work. But after he filmed the water flowing, even the one flowing from his toilet, he wondered where it was travelling to and what kind of water was coming to the Sava. The pleasant student Ivan Čizmin came to the Central Wastewater Treatment Plant of the City of Zagreb to get these answers and his shots. He had the idea to take a few shots of the water, but after seeing the size and complexity of the device he realized he would prefer to spend the night there. However, after a few hours of dedicated work, Ivan recorded dirty water of a million inhabitants on the entrance shaft. He was impressed by the overflow facility and biological pools, and he was satisfied with the recorded material. For a complete impression, he also went to the exit, where clean water from the main drainage channel flows into after the device goes into the Sava River. We believe that Ivan's work will be noticed and that in the future, when he becomes a graduate cameraman, he will continue to promote the importance of such projects for ecology.