Aims The purpose of this study was to evaluate the effects of temperature, mixing and sunlight exposure on the 5-day survival of Escherichia coli, Enterococcus sp., F+/male-specific coliphages, somatic coliphages and Clostridium perfringens spores in an 80/20 blend of surface water and reclaimed water approved for potable reuse in North Carolina. Methods and Results Grab samples of tertiary treated, dual disinfected North Carolina 'Type 2' reclaimed water were collected and mixed with ambient surface waters to create the 80/20 mix and then spiked with naturally occurring organisms present in the blended water or organisms isolated from sewage. Organism survival over the 5-day period was evaluated at 4 and 20 degrees C, 0, 60 and 120 rev min(-1) mixing speeds and exposure to sunlight or darkness. The log(10) survival ratio was then calculated for each organism at each condition. Conclusions There were measurable differences between the log(10) survival ratios at 5 days for most organisms; indicating that storage can decrease microbial concentrations. Mixing conditions were not a significant factor in microbe survival over the 5-day storage period. Sunlight was the most effective treatment factor to decrease log(10) survival during 5-day storage. Significance and Impact of the Study: No previous studies have evaluated the survival of micro-organisms in the NC approved 80/20 blend of surface and reclaimed water over the 5-day storage. This study provides the first results on the survival of regulated faecal indicator organisms stored for 5 days in blended water under different environmental conditions.