根据地表水处理规则（SWTR），纽约市必须过滤其卡茨基尔特拉华供水，除非其能够满足避免过滤的标准。1992年夏天，美国环境保护局（USEPA）任命了一个小组，就是否授予纽约市避免过滤的许可向该机构提出建议。专家小组得出结论，尽管水质标准基本上得到了满足，但流域控制的要求并未得到满足。专家组还得出结论，该市可能无法满足强化SWTR的水质要求，其中可能包括控制隐孢子虫的措施，以及其他附加要求。 尽管专家组提出了过滤建议，美国环保局还是批准纽约市在1993年、1996年、1999年和2002年期间避免过滤。尽管该市已经与卡茨基尔特拉华流域的北部社区协商达成了一项非常有用的流域协议，但问题仍然是一样的。本文评估了涉及的问题。包括34个参考文献、表格、图表。

Under the Surface Water Treatment Rule (SWTR), New York City is required to filter its Catskill-Delaware water supply unless it can meet the criteria to avoid filtration. A panel was appointed by the US Environmental Protection Agency (USEPA) in the summer of 1992 to advise the agency about whether to grant New York City permission to avoid filtration. The panel concluded that although the water quality criteria were met marginally, the requirements for watershed control were not met. The panel also concluded that the city would probably not be able to meet the water quality requirements of an enhanced SWTR, which would likely include, among other additional requirements, measures to control Cryptosporidium. Despite the panel's recommendations for filtration, USEPA granted New York City an avoidance of filtration first through 1993, then through 1996, 1999, and 2002. Although the city has negotiated a very useful watershed agreement with the upstate communities in the Catskill-Delaware watershed, the issues remain the same. This article assesses the issues involved. Includes 34 references, tables, figures.