AWWA JAW71676

Data from four large water systems in Utah were used to assess the validity of monitoring for Escherichia coli in lieu of Cryptosporidium to assess source water vulnerability to Cryptosporidium oocysts. In the geographic area reported on here, the participating water utilities concluded that monitoring for the occurrence of bacteria such as E. coli would not provide reliable information about the occurrence of pathogenic organisms such as Cryptosporidium. Surrogates, though cheaper to analyze for, may not provide a good indication of the exposure to target pathogens. Water providers may want to consider the findings that are detailed here as they look for answers about their own source water and future requirements, both from a cost perspective and the level of treatment that will be required. For utilities, especially small systems, monitoring for pathogens may be more expensive than monitoring for fecal bacteria but could pay off in terms of reduced risk to public health and greater peace of mind. Includes 27 references, tables, figures.