本文讨论了降低现有饮用水砷最高污染水平（MCL）将如何给美国的供水商带来巨大的合规成本。制定了一套严格的方法来估算遵守砷替代监管限值的国家成本。现有的水处理技术和方法的可行性并不是基于现有水处理技术的性能。选择治疗替代方案的最低成本法被用于估计依从性成本，结果在全国范围内外推。包括35个参考文献、表格和图表。

This article discusses how decreasing the existing arsenic maximum contaminant level (MCL) for drinking water will impose substantial compliance costs on water suppliers in the United States. A rigorous methodology was developed to estimate the national cost of complying with alternative regulatory limits for arsenic. This methodology considered the feasibility of available technologies based on existing treatment at utilities that are not in compliance and the level of water quality constituents that limit technology performance. A least-cost method of selecting treatment alternatives was used to estimate compliance costs, and the results were extrapolated nationally. Includes 35 references, tables, figures.