In February 1977, a massive discharge of carbon tetrachloride into the Kanawha River in West Virginia threatened much of the Ohio River Valley with contaminated drinking water potentially affecting over one million consumers. The episode heightened the awareness of consumers and decision-makers alike to the relationship between wastewater discharges and drinking water consumption. In the paper the results of a study designed to examine the interactions between industrial discharges and drinking water consumption in surface water supplies is examined. The mechanism used to study the wastewater discharge water supply intake interaction was a water quality/quantity simulation model, QUAL-II. QUAL-II was used to provide a framework to bring the diverse elements of mathematical modeling, fluid dynamics, epidemiology, organic chemistry and geography to create an interactive systems analysis approach that can have an impact on public policy in drinking water. (Copyright (c) 1985, Baywood Publishing Co., Inc.)