This collection contains open data and open publications of the results of the H2020 funded project NICE. NICE will widen the availability of enhanced nature-based solutions (NBS) to provide circular urban water solutions. The project will provide key knowledge for the design and implementation of NBS, closing urban water loops, mitigating pollution and runoff. NICE will study existing and innovative NBS covering the urban water cycle (wastewater, greywater, river basins, stormwater and combined sewer overflow). High-potential technologies (green walls, vegetated rooftops, rain gardens and hybrid subsurface wetlands) will be studied and enhanced with tailored bioaugmentation strategies, reactive materials and other filling media, novel design and plants, obtaining highly efficient urban water NBS. This approach will involve research, citizens, policy and the economic sector to provide the knowledge-base for the integration of NBS into the real world.