NBER Working Papers · 2026 · David A. Keiser、Bhashkar Mazumder、David Molitor、Joseph S. Shapiro
中文摘要
自1974年《安全饮用水法》颁布以来，美国已投入2万亿美元用于提供安全饮用水，但仍有10%—20%的美国人的饮用水不符合标准。我们研究美国饮用水污染的趋势、成因与后果，使用了通过数十项《信息自由法》申请及相关请求从48个州获得的、跨越数十年且涵盖1,250种污染物的2.66亿条检测记录。我们将污染数据与关于美国老年人健康结局的联邦医疗保险行政数据相匹配。研究得到三项发现。第一，美国饮用水污染迅速下降；2003—2019年间，超过现行健康标准的检测记录占比下降了一半。未受监管污染物的下降速度较慢。低收入地区的污染程度更高；黑人和西班牙裔社区则呈现更为复杂的模式。第二，《安全饮用水法》向供水系统提供的贷款减少了污染。按照估计的平均贷款成本效益计算，每人每年花费46美元即可利用这些贷款消除超过健康标准的污染。第三，这些贷款降低了美国老年人的死亡率。尽管财政联邦主义告诫，不宜由联邦政府为饮用水这类辖区间外部性较少的地方公共品提供资金，但我们估计《安全饮用水法》贷款带来了巨大收益。
Abstract
Since the 1974 Safe Drinking Water Act, the U.S. has spent $2 trillion to provide safe drinking water, yet drinking water for 10–20 percent of Americans violates standards. We study trends, causes, and consequences of U.S. drinking water pollution, using 266 million readings on 1,250 pollutants over decades that we obtained from 48 states via dozens of Freedom of Information Act and associated requests. We link pollution to administrative Medicare data on older Americans' health outcomes. Three findings emerge. First, U.S. drinking water pollution has declined rapidly; the share of readings exceeding current health standards fell by half from 2003–2019. Unregulated pollutants declined more slowly. Low-income areas have higher pollution; Black and Hispanic communities have more complex patterns. Second, loans provided by the Safe Drinking Water Act to water systems reduce pollution. At the estimated average loan cost-effectiveness, these loans could eliminate pollution above health standards for $46 annually per person. Third, these loans reduce mortality rates of older Americans. Although fiscal federalism cautions against federal funding of local public goods with few inter-jurisdictional externalities like drinking water, we estimate large benefits from Safe Drinking Water Act loans.