Assessing the impact of tiered water pricing policy on residential water consumption in China: A national evaluation and spatial heterogeneity analysis

Tiered water pricing is a key policy instrument for managing urban residential water demand, with its effectiveness critically depends on how pricing structures are designed. However, existing evidence remains limited in providing a nationally consistent and spatially explicit assessment of how the core design parameters of volumetric thresholds, price levels, and gradients jointly influence residential water consumption. In this study, the implementation of tiered water pricing across 284 municipal cities in China is systematically evaluated, and double-log regression and geographically weighted regression methods are employed to assess how the core parameters of tiered water pricing influence urban residential water consumption. The results reveal pronounced north–south differentiation in pricing structures, with higher price levels prevailing in water-scarce northern regions and more generous volumetric thresholds concentrated in southern regions characterized by higher precipitation. At the national scale, residential water consumption responds significantly to threshold volumes, price levels, and price gradients, underscoring the importance of coordinated policy design. The estimated effects display pronounced spatial heterogeneity across cities, which is consistent with regional differences in economic development, water resource endowments, and climatic conditions. These findings provide empirical support for context-specific pricing reforms aimed at improving urban water conservation outcomes.