The sustainable development of our cities and regions has become an integral part of the current debate. To achieve the sustainability goals, however, the development of sustainable technologies and infrastructures as well as decisive municipal action at the local level are essential. The research project VertiKKA (“Vertical Air Conditioning and Wastewater Treatment System”), sponsored by the German Ministry of Education and Research, addresses both technology development and the integration of innovative technologies and infrastructures into urban planning and decision-making processes. As a result, a set of indicators was developed that allows the assessment of urban infrastructures and technologies and their contribution to sustainable development. This article presents the “set of indicators for sustainable urban infrastructures” (ISI). ISI is based on the results of literature and policy review but was further developed and tailored to urban infrastructures and technologies. ISI considers the ecological, economic, and social dimension of sustainability to be of equal importance; in addition, ISI places particular emphasis on looking at the technology development process and on the creation of supportive governance structures for implementation. In order to create a link between research and practice, the applicability of ISI to the VertiKKA technology is critically reflected.