n 1999, the Methods Research and Development Program of the U.S. Geological Survey National Water Quality Laboratory began the process of developing a method designed to identify and quantify human-health pharmaceuti- cals in four filtered water-sample types: reagent water, ground water, surface water minimally affected by human contribu- tions, and surface water that contains a substantial fraction of treated wastewater. Compounds derived from human pharma- ceutical and personal-care product use, which enter the envi- ronment through wastewater discharge, are a newly emerging area of concern; this method was intended to fulfill the need for a highly sensitive and highly selective means to identify and quantify 14 commonly used human pharmaceuticals in filtered-water samples. The concentrations of 12 pharmaceu- ticals are reported without qualification; the concentrations of two pharmaceuticals are reported as estimates because long- term reagent-spike sample recoveries fall below acceptance criteria for reporting concentrations without qualification.