AWWA JAW39294

From consideration of prior monitoring studies on finished water Cryptosporidium and measurements made during and after detected outbreaks, an action level for Cryptosporidium oocysts is defined. At concentrations within and above 10-30 oocysts/100 L in finished water, the possibility of an outbreak would appear to exist. In the lower range of this region and below, outbreaks may occur but may not be detectable. If a single sample exhibits counts at or above this level, further sampling on an expedited basis or consideration of supplemental performance data to support a decision should be undertaken. Includes 13 references, table, figure.