本文概述了第五阶段规则。第五阶段规则为23种污染物制定了法规，其中22种来自SDWA授权监管的83种污染物清单。这些新规定适用于所有社区和非临时性非社区水系统。本文讨论了污染物的MCLGs和MCLs集、合规性监测、批准的分析方法、最佳可用技术（BAT）、差异和豁免条件，以及成本和效益。一个表格列出了每种污染物、其健康影响、MCLG和MCL，以及水中污染物的来源。第二个表格给出了每类污染物（无机物、氰化物、挥发性有机化合物、农药和SOC）的合规性监测要求。 第三个表列出了分析方法，第四个表列出了每种污染物的BAT，最后一个表列出了整个规则的估计成本。包括3个参考文献、表格。

This article gives an overview of the Phase V rule. The Phase V rule establishes regulations for 23 contaminants, 22 of which are from the list of 83 contaminants mandated for regulation by the SDWA. These new regulations apply to all community and nontransient noncommunity water systems. This paper discusses the MCLGs and MCLs set for the contaminants, compliance monitoring, approved analytical methods, best available technologies (BATs), conditions for variances and exemptions, and costs and benefits. A table lists each of the contaminants, its health effects, MCLG and MCL, and source of the contaminant in the water. A second table gives compliance monitoring requirements for each class of contaminant (inorganics, cyanide, VOCs, and pesticides and SOCs). A third table lists analytical methods, a fourth table lists the BAT for each contaminant, and a final table lists estimated costs of the rule as a whole. Includes 3 references, tables.