water-quality testing, and certiﬁed treatment devices (U.S. EPA 2006d). Some states have initiated measures to assess water quality to aid in the protection of human health. For example, New Jersey passed a law in 2002 that requires private domestic well owners to test “raw” or untreated water for contami- nants, including regulated VOCs, and to dis- close results before selling or leasing properties (New Jersey Department of Environmental Protection 2006). Furthermore, some law- makers have introduced bills in Congress that would mandate testing of private wells throughout the United States. Future direction and challenges. Science- based strategies are needed for identiﬁcation of contaminants that are not regulated but may be present in drinking water from domestic wells. In addition, assessing the occurrence of contaminants from products that may be of current and future concern (e.g., personal care products, food additives, detergents, and pharmaceuticals) is war- ranted. Providing information on the occur- rence of contaminants in drinking water from domestic wells is important for local, state, and federal water-resource managers and others charged with protecting and man- aging drinking-water resources. In addition, because many organic contaminants do not have human-health benchmarks, continued research is needed to provide the toxicologic data necessary to develop these benchmarks, which in turn provide tools for evaluating water-quality data in the context of human health. Previously sampled wells, such as those included in the present study, could be resampled to further assess water-quality conditions and to determine variability and trends in contaminant occurrence and con- centrations. Data collected systematically over a period of time could aid in determin- ing whether a correlation exists between an identified contaminant source and VOC occurrence in a drinking-water supply. In addition, domestic wells that are located near areas that are known to be associated with contaminant sources could be targeted for monitoring. At domestic well sampling sites, well char- acteristics and pumping information may be available; however, a challenge for future stud- ies is to obtain ancillary information relevant to human health for domestic well users. For example, standard questionnaires could accompany sampling activities. If used, the type of household water-treatment systems could be identified, such as granulated activated-carbon for removal of VOCs, and supplementary drinking-water sources, including bottled water, could be determined. Additional pertinent information could include the number and age of household members, amount of water ingested, length of time using the water supply, and upgrades or changes in the household-water system since the initial installation at the time of the home construction. 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