Decentralized water reuse in cities is a prominent alternative to mainstream top-down models for urban water treatment, which are based on centralized, linear dynamics of resource management. In this sense, Nature-based Solutions (“green” technologies) coupled with advanced technologies (“grey” technologies) constitute a promising approach for fomenting onsite water treatment and reuse in cities, while also providing multiple co-benefits. This article puts forward a conceptual advancement by providing a better understanding of coupled “green-grey”/“grey-green” technologies (CGGT).
