根据现行联邦法律，服务于1万人以下的公共供水不需要监测或控制三卤甲烷（THM）。对爱荷华州的小型供水设施进行了调查，以确定THM污染是否是一个问题，并确定适合小型供水设施的THM控制措施。1983年7月、8月和1984年9月，从处理设施和人口不足1万的社区的分配系统中采集了抓取样本。超过75%的社区THM水平超过最大污染物水平。对影响三卤甲烷形成的处理改造进行了审查，并推荐了适用于小型公用事业的控制措施。包括18个参考文献、表格、图表。

Under current federal law, public water supplies that serve fewer than 10,000 people are not required to monitor or control trihalomethanes (THMs). Small water utilities in Iowa were surveyed to determine whether THM contamination is a problem and to identify measures for THM control appropriate for small utilities. Grab samples were collected in July and August 1983 and September 1984 from treatment facilities and from distribution systems in communities with fewer than 10,000 residents. More than 75 percent of the communities had THM levels in excess of the maximum contaminant level. Treatment modifications that influence the formation of THMs are reviewed and control measures appropriate for small utilities are recommended. Includes 18 references, tables, figures.