居民阶梯水价制度产生节水效应了吗?——来自杭州的新证据

Has the tiered water pricing system produced water-saving effects? New evidence from Hangzhou

立足于居民阶梯水价制度改革的具体实践,基于分段约束效用函数的设计思路,利用2012—2022年杭州市居民阶梯水价及家庭户用水量的面板数据,对居民阶梯水价制度的节水效应开展实证研究。基准回归结果显示,居民阶梯水价制度在总体上存在节水效应;分类检验显示,第一阶梯水价是产生节水效应的重要渠道,但第二阶梯和第三阶梯水价均未产生显著的节水效应。多重固定效应分析、随机抽样的安慰剂检验以及内生性检验均证实了基准结果的稳健性。异质性分析发现,居民阶梯水价制度在不同规模的用水量家庭和不同区域间呈现差异化特征;分位数回归发现,水价在总样本0.75的分位点上产生节水效应;交叉效应则显示,千岛湖配水工程使阶梯水价制度产生了用水促进效应。上述研究结果表明,杭州市居民阶梯水价制度产生了一定的节水效应,但是尚未完全发挥节水作用。该研究为城市水价机制改革提供了来自杭州的经验证据,对进一步优化城市居民阶梯水价制度具有一定的政策启发。

Based on the specific practice of the reform of the tiered water pricing system and the design idea of segmented constraint utility function,an empirical study of the water-saving effect of the tiered water pricing system is carried out by using panel data on the tiered water pricing and household water consumption in Hangzhou from 2012 to 2022.The results of the benchmark regression show that there is a significant water saving effect of the tiered water pricing system on the whole,and classification tests show that the first-tier water pricing produces a significant water-saving effect within the total effects,while neither the second-tier nor the third-tier water pricing produces a significant water saving effect.And the robustness of the results is confirmed by multiple fixed-effect analysis,placebo tests with random sampling and endogeneity tests.The heterogeneity analysis shows that the tiered water pricing system is differentiated among households with different scales of water consumption and different regions.The quantile regression shows that the water pricing produces a water-saving effect at the 0.75 quantile of the total sample,but the cross effect with the Thousand Island Lake Water Distribution Project produces a water use promotion effect.The findings of the study indicate that the tiered water pricing system for residents in Hangzhou has produced a certain water-saving effect,but it has not yet fully played a watersaving role.This study provides empirical evidence from Hangzhou for the reform of water pricing mechanisms and proposes recommendations for further optimizing the tiered water pricing system.