Water –the most vital resource, negatively affected by the linear pattern of growth –still tries to find its positioning within the emerging concept of circular economy. Fragmented, sectorial circularity approaches hide the risk of underestimating both the preservation of and impacts to water resources and natu- ral capital. In this study, a game changing circularity assessment framework is developed (i.e. MSWCA). The MSWCA follows a multi-sectoral systems approach, symbiotically managing key water-related socio- economic (i.e. urban water, agro-food, energy, industry and waste handling) and non-economic (i.e. nat- ural environment) sectors. The MSWCA modelling framework enables the investigation of the feedback loops between the nature-managed and human-managed systems to assess water and water-related re- sources circularity. The three CE principles lie at the core of the developed framework, enabling the con- sideration of physical, technical, environmental and economic aspects. An indicators database is further developed, including all the relevant data requirements, as well as existing and newly developed indi- cators assessing multi-sectoral systems’ circularity. The MSWCA framework is conceptually applied to a fictional city, facilitating its understanding and practical use.