在1992年1月至1993年12月期间，大约7700家美国大中型公共供水商根据铅和铜规则对自来水进行了最近的监测，其中一些供应商正在实施处理调整，现在有了一个新的机会来研究哪些措施可能显著降低住宅自来水中的铅和铜含量。因此，本研究的一个主要目的是开始利用这一新兴的数据和经验，通过严格的统计分析，确定什么样的水质特征和/或处理改进可以在统计上降低居民的铅和铜水平，以及在多大程度上降低。这项研究采用了两种独特的方法，将它们结合起来，以更好地了解自来水铅的动态，并为公共供水商提供一个更清晰的画面，说明降低第90百分位铅水平的各种方案的有效性。 第一种方法是从美国各地招募志愿者，他们来自各个年龄段的家庭和管道系统类型，对他们的水进行铅测试，交换条件是提供有关他们住所的信息。第二种方法涉及对美国公共供水的成品水质量和处理方法进行广泛调查，然后将这些数据与根据铅和铜规则在前两轮监测中观察到的系统第90百分位铅水平进行统计关联。

With the recent at-the-tap monitoring under the Lead and Copper Rule by approximately 7700 large and medium-sized US public water suppliers between January 1992 and December 1993, and with the treatment adjustments being implemented by some of these suppliers, a new opportunity now exists for examining what measures are likely to significantly reduce residential tapwater lead and copper levels. Thus, a primary purpose of this research is to begin to harness this emerging body of data and experience to determine through rigorous statistics analysis what water quality characteristics and/or treatment modifications can be expected to statistically reduce residential lead and copper levels and to what extent. This research utilized two distinctive methodologies which are combined to develop a better understanding of tapwater lead dynamics and to provide public water suppliers a clearer picture of the effectiveness of various options for reducing 90th percentile lead levels. The first methodology involves recruitment of volunteers from across the US from all ages of homes and plumbing system types to have their water tested for lead in exchange for providing information about their residence. The second methodology involved an extensive survey of US public water supplies for their finished water quality and treatment methods followed by a statistical correlation of these data with the 90th percentile lead levels observed for their systems during the first two rounds of monitoring under the Lead and Copper Rule.