Bank filtration sites rely on hydrologic processes of filtration to remove pathogens from drinking water sources. This study investigated the impact of ash leachate generated from fires on the bank filtration removal of parasites including Cryptosporidium parvum. The transport of C. parvum, surrogate latex microspheres, and E. coli through packed sediment columns was examined in the presence of wildfire ash leachate. Increases in leachate concentration resulted in increased retention, despite theoretical predictions of high dissolved organic carbon and phosphate concentrations in leachate, predicting increased transport. In these studies, E.coli was retained more than C. parvum oocysts, possibly due to the smaller size and elongated shape of the bacteria. When columns were flushed first with ash leachate and parasites were retained, but then washed with river water, at least 10% of the parasites were transported. Ash leachate seems to favor retention of pathogens and suggests that fire may not be problematic for bank filtration systems.