A transferable environmental responsibility framework for provincial water footprints: Production–consumption interaction patterns and inequality in China

Spatial separation between production, consumption, and environmental burdens complicates responsibility allocation in water footprint assessment. This study developed a transferable environmental responsibility framework and used China's 31 provinces as an empirical case to assess blue, green, and grey water footprints from production and consumption perspectives. By integrating top-down and bottom-up accounting with a water footprint extended multi-regional input-output model, we quantified production-side external contribution, consumption-side external dependence, and their relative balance. Provinces were classified into four interaction pattern groups, and environmental inequality was evaluated using the Theil index. Virtual water flows formed a pronounced interprovincial network in which southeastern coastal provinces acted as major demand hubs, whereas many northeastern and northwestern provinces served as net suppliers of embodied water use and pollution burdens. The environmental responsibility coefficient showed strong validity, exhibiting significant positive correlations with provincial net transfer roles. The weighted Theil index indicated a moderate level of national inequality. Blue water footprint inequality was consistently dominated by between-group differences, grey water footprint inequality by within-group heterogeneity, and green water footprint inequality showed relatively balanced between-group and within-group contributions. Robustness tests based on median- and mean-based thresholds preserved the main conclusions for blue and grey water footprints, while indicating greater threshold sensitivity for green water footprints. The framework and findings provide transferable insights for multi-regional systems where production, consumption, and environmental burdens are spatially decoupled.