This collection of articles emphasizes the value of determining the costs associated with water-borne externalities. Pecuniary, technical, marginal and inframarginal externalities are defined and their effects on societies' production possibilities are examined. A survey was made to determine the loss of commercial fishing income arising from a fishing ban on an Alabama lake caused by mercury pollution. Total income loss to fishermen was mitigated by shifting their resources to other uses; as a result, it appears that only 15 commerical fishermen suffered income losses. The effect of production, consumption and disposal decisions on level and form of residuals was also examined. The modeling effort illustrates the flow of residuals and costs arising from power generation from either coal or nuclear fuel. The effect of water quality on regional growth was examined using an input-output model. A decrease in usable water was traced to show its composite effect on income, consumption, and governmental expenditures and revenues.