A team of investigators from the University of Kansas, Virginia Polytechnic Institute & State University (Virginia Tech), and Black & Veatch, in cooperation with investigators from the American Water Works Service Company and the University of Notre Dame and with the cooperation and assistance of 19 water utilities, is conducting a comprehensive assessment of disinfection byproduct (DBP) precursor removal by enhanced coagulation and softening. The primary objective of this research project, sponsored by the AWWA Research Foundation, is to determine the degree to which DBP precursor removal by conventional coagulation and softening can be improved in full-scale plants and to examine the advantages, disadvantages, and costs of doing so. The objectives of this paper are: to summarize the preliminary results of the water quality survey; to present a summary of the results obtained from bench-scale tests and sampling of full-scale plants; and to identify some of the potential benefits and detriments associated with enhanced precursor removal.