What is the most critical parameter to monitor when managing a hospital's domestic hot water system to prevent Legionella growth?

The most critical parameter to monitor when managing a hospital's domestic hot water system to prevent Legionella growth is the water temperature. Legionella bacteria thrive in temperatures between 77°F (25°C) and 113°F (45°C). To effectively control Legionella, it is crucial to maintain the hot water supply temperature above 140°F (60°C) and ensure that the return water temperature remains above 124°F (51°C). Regular monitoring of water temperatures at various points in the system, including the hot water heater outlet, the furthest points in the distribution system, and the return line, is essential. Automated temperature monitoring systems with alarms can provide real-time alerts if temperatures fall below the recommended levels. Maintaining these temperatures inhibits the growth and survival of Legionella bacteria, reducing the risk of Legionnaires' disease. In addition to temperature monitoring, other important factors include maintaining adequate disinfectant levels and controlling biofilm formation, but temperature control is the most critical factor.