HACCP is a food safety management system that can also be applied to drinking water supply. It has not, as far as we know, been formally introduced for this purpose. However, concepts of total quality management and quantative risk assessment are increasingly being used to assure safe drinking water. In this paper the integration of these concepts is discussed. The major microbiological hazards in drinking water supply are pollution of raw water sources, recontamination of storage and distribution facilities for treated water and growth of pathogens in raw and treated waters. In ground water supply, protection of the aquifers is the essential critical control point (CCP); if this cannot be assured, additional disinfection of the abstracted water will be necessary. In surface water supply, several CCPs can be identified including coagulation/flocculation/sedimentation/filtration and (chemical) disinfection. Recontamination of treated waters is also a major CCP. Several steps are important to assure the quality of the final water, but cannot be considered to be CCPs under the responsibility of the water producer because of a lack of a direct control. These include the quality of abstracted waters, the effect of raw water storage reservoirs and growth of microorganisms in the distribution or plumbing systems. Surveillance of these steps is, however, essential to properly define the critical limits for the above-mentioned CCPs.