Legionnaires' disease is foreseeable and preventable, but disease case numbers are not going down. Since the first Legionnaires' disease outbreak nearly 50 years ago we have learned a great deal about the organism and disease, but in some water systems, Legionella risks may still be poorly managed. This Conference will explore some of the complexities of managing water systems and consider how Legionella control can be designed into the life cycle of water systems.