The main purpose of water companies is to deliver to each consumer safe drinking water(DW)and free from any microbes. Drinking water distribution systems (DWDS) are known to harbor biofilm, even in the presence of a disinfectant. These biofilm is a source of planktonic bacteria , which will remain present when the water is delivered through a consumer’s tap. The presence of biofilm in DWDS constitutes one of the currently recognized hazards affecting the microbiological quality of the product and may lead to a number of unwanted effects on the organoleptic quality of the distributed water. Importantly, biofilm constitute a persistent reservoir of pathogenic microorganisms, which are responsible for several waterborne diseases. Antimicrobial products, particularly chlorine, have been the main weapons used to disinfect DW.