Water is a best medium for many MICROORGANISMS, microorganism can be a highly PATHOGENIC which causes serious diseases(many diseases are water born), these pathogens infect after consumption of CONTAMINATED water, microorganisms tend to settle on a surface if water is allowed to stand in a stagnant POSITION for few hours, these settled microorganism form a film over the surface of vessel and piping, such film formed by microorganisms is also called as biofilm, biofilms are very difficult of remove, once a biofilm is formed at a particular point then that point may form a biofilm again even after cleaning very easily as seed from this point is may not COMPLETELY get removed effectively.

Water is a best medium for many microorganisms, microorganism can be a highly pathogenic which causes serious diseases(many diseases are water born), these pathogens infect after consumption of contaminated water, microorganisms tend to settle on a surface if water is allowed to stand in a stagnant position for few hours, these settled microorganism form a film over the surface of vessel and piping, such film formed by microorganisms is also called as biofilm, biofilms are very difficult of remove, once a biofilm is formed at a particular point then that point may form a biofilm again even after cleaning very easily as seed from this point is may not completely get removed effectively.