This article presents results from a study that attempted to optimize removal of asbestos particles at five large water treatment plants receiving low to high concentrations of chrysotile asbestos fibers in their influents. The analytical method used in the study involved passing a sample through a membrane filter and transferring part of the filter to a grid on which the fibers can be observed by using a transmission electron microscope. Treatment techniques employed by the tested water treatment plants were also analyzed. The ability of each plant to remove asbestos fibers was dependent on the asbestos concentration in the influent and on the efficiencies of the individual treatment processes. Optimized treatment resulted in lower effluent asbestos concentrations than standard treatment. Includes 12 references, tables, figures.