What should a university do to support citizen science initiatives within an open science context, and to assist and facilitate researchers in performing effective citizen science? Delft University of Technology (TU Delft) has developed an open science program that includes, among other projects, citizen science. However, performing citizen science is not a straightforward task. For the people designing and managing citizen science projects, it demands appropriate knowledge, understanding, and experience of the field, as well as knowledge of the practical implementation of citizen science and open science. This requires a deeper understanding of which extra-academic skills, collaborations, rewards, and recognitions are needed for a citizen science project. Therefore, we used a local, hydrological citizen science project, “Delft Measures Rain,” as a case-study, implementing citizen science methods and the TU Delft Open Science principles. By means of this case-study, we identify key tools and facilitation needs to assist researchers within TU Delft to perform effective citizen science and open science. This paper shows how the various stakeholders (i.e., researchers, citizens, civil servants, and NGO’s) can benefit from performing participatory research implementing citizen science and open science principles. We list 10 key elements, encompassing tools, facilitation, and infrastructures that universities can provide for their researchers to stimulate and support the implementation and execution of successful, legally sound, and open citizen science. This case study shows that with appropriate and extra-academic knowledge, tools, collaborations, rewards, and recognitions, citizen science can deliver what it promises and be of great value to universities and open science in general.