Results of the first study concerning the impact of acid precipitation on drinking water are reported in terms of health effects in humans as measured by the U.S. Environmental Protection Agency maximum contaminant levels. The study focused on sampling surface water and groundwater supplies in the New England states but also included other sites in the Northeast and the Appalachians. No adverse effects on human health were demonstrated, although the highly corrosive nature of New England waters may be at least partly attributable to acidic deposition in poorly buffered watersheds and aquifers.