The objective of this article is to present the major concepts of bacterial regrowth modeling for distribution systems and to show a particular model application. In the first part, the article describes the processes which were taken into account by the PICCOBIO bacterial regrowth model, developed by the CIRSEE research center of the Suez Lyonnaise des Eaux group, and points out the aspects which are to be integrated in the forthcoming model development. In the second part the article shows how modeling can contribute to the understanding of the relationship between environmental parameters (temperature, substrate concentration, inlet bacteria concentration) and bacterial dynamics in the drinking water distribution system. Includes 23 references, table, figures.