Against the backdrop of several outbreaks of legionellosis caused by the bacterium Legionella pneumophila from technical water systems in Germany in recent years, the legislature adopted the 42nd Ordinance Implementing the Federal Immission Control Act (42nd BImSchV) in 2017. This affects facilities that use water at elevated temperatures, in particular scrubbers in electroplating plants or paint shops. The Regulation requires businesses to carry out regular tests to check whether the water used contains bacteria. Even though the exact procedure for the tests and the monitoring by the authorities have not yet been clarified in detail, the businesses concerned must register with the new government database KaVKA (Register for the Recording of Evaporative Cooling Systems).