An integrated chemical analytical and biological approach was used to detect the presence of genotoxins in the drinking water of four Italian cities which obtain their water supply from different sources (superficial or source waters). A battery of rapid and sensible in-vitro and in-vivo tests were used to detect genotoxic compounds, and chemical analytical methods to detect disinfection by-products. The aim was to provide information useful for routine monitoring of drinking water and recommendations for improving the management of disinfection and distribution establishments.