The evaluation of 16 sites with optimized coagulation (optimizing the pH of coagulation and then the coagulant dosage) provides an assessment of this coagulation technique and illustrates its capabilities to meet the requirements of the Disinfectants/Disinfection Byproducts (D/DBP) Rule. Jar tests were used to determine the effectiveness of optimized coagulation for the removal of organic carbon, DBP precursors, particles, and turbidity when supernatant results were compared with conventional (baseline) treatment. Jar-test results indicate that optimized coagulation can enhance the removal of organic carbon and DBPprecursors. Includes 17 references, tables, figures.