Overview and comparison of Legionella regulations worldwide

Background Legionnaires disease occurs worldwide. Many authorities have guidelines and regulations to prevent and control Legionella in water systems. These regulations are based on often very limited field and laboratory observations and measurements. They are, therefore, very different from country to country. This article aims to map the existing regulatory framework of worldwide Legionella control to assess the feasibility of regulatory unification. Methods This article gives an overview of the different standards, guidelines, and recommendations as well as how various authorities and/or countries deal with Legionella infection. A 3-step process is followed to identify current regulations. Results Although Legionella is a global concern with a common scientific base, the regulatory framework is different from country to country. The current guidelines and standards are not the best possible. Despite different regulatory frameworks, there is still broad unification of underlying principles. Common principles across regulations are avoiding and monitoring critical spots, avoiding water stagnation, and maintaining sufficiently high temperature (above 60°C, below 25°C). Differences between regulations are target group and dangerous Legionella concentration levels. Conclusions The comparative analysis of the framework is a good starting point for reaching future regulatory unification based on common ground.