In order to answer the question posed by the conference Urban Europe, Precarious Futures? the article examines the relationship between rising precariousness,the need for social-ecological transformation to keep socio-ecological environments manageable for future generations of Europeans and the provision of urban reliance systems as the key pillar of a possible transformation toward life within the planetary boundaries. The article has four goals: First, it establishes a link between the literatures on precarization, three possible political-economic development scenarios, and resulting modes of urban governance. Second, it develops the normative but theoretically and empirically backed claim that a strengthening of the foundational economy appears most suited to produce the necessary reductions in precarious living conditions and environmental destruction required for a socially and ecologically sustainable future. Third, the urban scale is argued to occupy a privileged position as a growing site of human habitation in Europe and for the design and provision of foundational infrastructure and universal basic services. The article links cities to the foundational economy via the concept of the Grounded City. Fourth, research on the provision of universal basic services in the City of Vienna is employed to illustrate that a narrow focus on cities as territorial-administrative containers ignoring their inter-territorial and inter-scalar relations is likely to produce socio-spatial rebound effects that may neutralize the gains of social-ecological investment in cities. Any effective social-ecological transformation thus requires coordination, cooperation, lobbying and political change at all scales of governance. In the European case, it requires the European Union to evolve from an economic to a social-ecological Union and for urban governance regimes across Europe to be altered to take into account the horizontal and intra-scalar relations that co-constitute cities.