The industrial Ohio River is the source water for Cincinnati Water Work's (CWW) California surface water treatment plant. As is true for many industrial rivers, a large number of organic contaminants can be found in trace concentrations in the Ohio River. Many Cincinnati citizens are concerned about the quality of the industrial source water because of the frequent spills and unauthorized discharges that occur each year. Because of citizen and utility manager concerns, granular activated carbon (GAC) research studies were completed at Cincinnati, Ohio. The results of these studies provided the impetus for a full-scale GAC addition to the existing Ohio River Plant. Ground breaking and full construction began on March 16, 1989, for a 175 MGD GAC system that includes downflow, gravity GAC adsorption and on-site multiple hearth reactivation. Completion of the 57.7 million dollar GAC addition is expected by 1992. The GAC plant will provide an additional barrier between the contaminants in the industrial Ohio River water source and the consumers of Cincinnati water. The paper will discuss vital but less publicized data and experiences obtained during the completion of the final design and implementation activities of the CWW.