Genetic evidence for the offsite transport of E. coli associated with land application of Class B biosolids on agricultural fields

► Heavy rainfall significantly increased E. coli in tile water draining from agricultural fields receiving biosolids. ► The genetic similarity of tile E. coli to those of biosolids correlated significantly with previous 72 h rainfall. ► Several E. coli isolated from drain tile water were genetically highly (> 94%) similar to those from biosolids. ► Land-applied biosolids were identified as a source contributing to decreased water quality in drain tiles.