Postharvest handling of potatoes regularly includes the use of flumes, dump tanks, and spray washers. Soil, plant matter, and disease-causing pathogens can potentially accumulate during postharvest water uses. This project evaluated the microbial quality of water used in potato packinghouse operations using generic Escherichia coli. Five potato packinghouse operations were sampled three times each during the season. At each visit, water and potato samples were collected in triplicate during two time-points (morning and afternoon). A total of 630 samples were collected. The average population of generic E. coli in flume water samples (n=90) was 413 MPN/100 milliliters, while the average population of generic E. coli in spray bar water (n=90) was below the limit of detection (<1 MPN/100 milliliters or zero detectable generic E. coli). Generic E. coli populations were significantly higher in flume water, compared with spray bar water. The average population of generic E. coli on potato samples from incoming bulk bodies/before entry into flumes, in flumes, post-flume/before spray bar, spray bar, and post-spray bar/before packing was 106, 386, 251, 3 and less than 1 MPN/100 milliliters, respectively. Populations of generic E. coli on potatoes were significantly higher on potatoes before the spray bar, compared to on potatoes after the spray bar. Thus, water used for the final rinse in the spray bar system was effective at reducing the quantity of generic E. coli on potatoes, as generic E. coli populations were below the limit of detection for all potato samples tested post-spray bar/after drying/before packing.