Stream water concentrations of fecal indicator bacteria, Escherichia coli and Enterococcus, were monitored in Tipton Creek, Beaver Creek and the South Fork of the Iowa River. These streams drain areas that have differing levels of swine and cattle production. Seasonal trends were present with populations greatest in summer and least in winter. Average E. coli concentrations in streams exceeded 150 cells/100 ml, but concentrations during runoff events reached 10⁵ cells/100 ml. A comparison of runoff from manured and non-manured cropped fields within the watershed indicated that wildlife could contribute approximately 30% of the E. coli transported off the field. E. coli and Enterococcus concentrations were significantly correlated, with Enterococcus concentrations tending to be larger.