The provision of safe drinking water (DW) is a top priority issue in any civilized society. Safe DW is a basic need to human development, health and well-being. The main challenge to the DW industry is to deliver a product that is microbiologically and chemically safe, aesthetically pleasing and adequate in quantity and delivery pressure. Normally, the water that leaves a treatment station has quality, but its quality decreases along the travel in the drinking water distribution systems (DWDS). Water industries and governments over the world are working together in order to improve DW quality through the effective treatment, monitoring of its physicochemical and microbiological properties, and the design and the operational management of the distribution networks. Although DW is strictly monitored in developed countries, waterborne outbreaks are still being reported due to microbial contamination. Biofilms contribute notoriously to these events, creating a protective and nutritional reservoir for pathogens growth and survival. Nevertheless, the dynamics of microbial growth in DW networks is very complex, as a large number of interacting processes (physicochemical and biological) are involved. DW biofilms constitute one of the major microbial problems in DWDS that most contributes to the deterioration of water quality. Although biofilm elimination from DWDS is almost impossible, several aspects can be manipulated in order to prevent and control their growth. This book chapter provides a contribution to better understand the important biological and ecological mechanisms involved in biofilm formation in DWDS, with intent to control and prevent their formation, in order to improve DW quality that reaches to consumer’s tap
