The health department of the regional association warns against excessively lowering the drinking water temperature in hot water tanks. This can have adverse effects on the quality of the drinking water and pose significant health risks. If systems for heating drinking water are not operated properly, harmful bacteria such as Legionella can develop. These can be inhaled through water vapor while showering, for example, and cause Legionnaires' disease. If left untreated, this disease can be fatal, especially for immunocompromised individuals.
To prevent the formation of legionella, a temperature of at least 60 degrees Celsius is recommended in hot water storage tanks. Below 20 degrees Celsius, the bacteria hardly multiply. However, water temperatures between 25 and 45 degrees Celsius provide ideal conditions for the reproduction of the disease-causing bacteria. Only from 55 degrees Celsius does the die-off begin. This accelerates many times over at 60 degrees Celsius.
Possible alternative energy-saving measures
To save energy costs, there are technical solutions as an alternative to reducing the hot water temperature. These include insulating exposed distribution pipes and heat storage tanks, as well as the hydraulic balancing of circulation pipes. Additionally, energy-efficient circulation pumps and efficient, economical heat generators can be used. All of these measures are hygienically safe. Further information has been summarized by the health department of the regional association in an information sheet on the risk posed by bacteria at too low hot water temperatures. It can be found online at www.regionalverband.de/trinkwasser
