本文讨论了美国环境保护局（USEPA）对现行国家初级饮用水法规（NPDWR）进行的第一次六年审查如何导致初步决定，即可以改进总大肠菌群规则（TCR），而目前68种化学污染物中没有一种适合修订。包括表、图。

This article discusses how the first six-year review by the US Environmental Protection Agency (USEPA) of current national primary drinking water regulations (NPDWRS) has resulted in a preliminary decision that the total coliform rule (TCR) can be improved, whereas none of 68 chemical contaminants is ripe for revision at this time. Includes table, figure.