Understanding the effectiveness of alternative approaches to water conservation is imperative for ensuring the security and reliability of water services for urban residents. We analyze data from one of the longest-running “cash for grass” policies – the Southern Nevada Water Authority's Water Smart Landscapes program – where homeowners are paid to replace grass with desert landscaping. We use a sixteen year long panel dataset of monthly water consumption records for 300,000 homes in Las Vegas, Nevada. We estimate the average water savings per square meter of turf removed with an event study and a panel difference-in-differences approach. We find that participation in this program reduced the average treated home's consumption by 20 percent. We find no evidence that water savings degrade as the landscape ages. Depending on the assumed time horizon of benefits from turf removal, we find that the Water Smart Landscapes program cost the water authority about $1.88 per thousand gallons of water saved, which compares favorably to alternative means of water conservation or supply augmentation.

为了确保城市居民供水服务的安全性和可靠性，必须了解替代节水方法的有效性。我们分析了运行时间最长的“以草换现金”政策中的一项数据–内华达州南部水务局的“水智能景观”计划，该计划向房主支付报酬，以用沙漠美化环境代替草。我们使用长达16年的面板数据集，为内华达州拉斯维加斯的30万户家庭每月的用水记录。我们通过事件研究和面板差异法估算了每平方米草皮平均节水量。我们发现，参与该计划使治疗后的家庭平均消费减少了20％。我们找不到证据表明节水随着景观的老化而降低。