The detection of Escherichia coli in drinking water supply systems traditionally indicates on the recent fecal pollution. However, this approach has occasionally failed to explain several waterborne outbreaks or sporadic occurrence of E. coli in distribution networks without apparent source of contamination. The overall aim of this thesis was to evaluate the significance of viable but non-culturable (VBNC) Escherichia coli in drinking water systems. During the work the selection and evaluation of appropriate molecular methods for enumeration of total and non-culturable E. coli in water and...