How Effective Are Building Codes at Reducing Residential Water Use? Evidence From California Billing Data
中文摘要
本研究利用加州账单数据,考察住宅用水效率标准对家庭用水量的影响。本文检验了《加州绿色建筑标准规范》(CALGreen)的短期与长期影响,比较了2010年该规范实施前后不久建造的住宅。结果显示,CALGreen住宅的用水量平均比可比的规范实施前住宅少11.7%,且节水效应随时间推移持续存在,约为10.9%。值得注意的是,基于工程测算的事前(ex ante)节水量估计几乎是实际实现的节水量的两倍,这可能反映了"抵消行为"效应。分析进一步发现,大部分节水发生在较暖月份,即户外用水达到峰值的时期。此外,CALGreen住宅对温度波动的敏感性较低:在较热月份用水量的增幅较小,在较凉月份用水量的降幅也较小。最后,在将合规成本与水的机会成本纳入考量后,结果表明CALGreen政策通过了成本有效性检验。这些发现凸显了建筑规范作为一种持久政策工具,在快速增长、半干旱地区实现长期节水方面的有效性。
Abstract
ABSTRACT This study examines the impact of residential water‐efficiency standards on household water consumption, utilizing billing data from California. I examine both the short‐ and long‐term impacts of the California Green Building Standards Code (CALGreen), comparing homes constructed just before and after its implementation in 2010. The findings show that, on average, CALGreen homes use 11.7% less water than comparable pre‐code homes, with savings persisting over time at approximately 10.9%. Notably, engineering‐based (ex ante) estimates of water savings are nearly twice as large as the realized reductions, likely reflecting the “offsetting behavior” effect. The analysis further reveals that most water savings occur during warmer months when outdoor water use peaks. In addition, CALGreen homes exhibit lower sensitivity to temperature fluctuations, with smaller increases in use during hotter months and smaller reductions during cooler months. Finally, when accounting for compliance costs and the opportunity cost of water, the results suggest that CALGreen policy passes a cost‐effectiveness test. These findings highlight the effectiveness of building codes as a durable policy tool for achieving long‐term water conservation in fast‐growing, semi‐arid regions.