对三种采样设计（每周、每月和空间聚类）进行比较，以确定它们在检测小型社区饮用水系统中大肠菌群污染方面的有效性。在一年的时间里，从佛蒙特州和新罕布什尔州农村的15个系统采集了水样。每月采样五次，无论是在一个系统（空间群）内的五个不同地点同时采集样本，还是在同一地点每周采集一次，检测到的污染事件比每月采样一次多50%到100%。在检测大肠菌群污染的能力方面，空间聚类设计比每周抽样设计略为敏感。包括6个参考文献、表格、图表。

Three sampling designs - weekly, monthly, and spatial cluster - are compared to determine their effectiveness in detecting coliform contamination in small community drinking water systems. Water samples were collected over a one-year period from 15 systems in rural Vermont and New Hampshire. Sampling five times a month, regardless of whether samples were collected simultaneously at five different sites within a system (spatial cluster) or once a week at the same site, detected between 50 and 100 percent more incidents of contamination than were found by sampling once a month. The spatial cluster design was slightly more sensitive than the weekly sampling design in its ability to detect coliform contamination. Includes 6 references, tables, figures.