The new version of the Drinking Water Ordinance (TrinkwV) became valid on 24.06.2023. The changes affect, among other things, the testing for legionella.
When evaluating the results, the following now applies the event that triggers the obligations is no longer the exceedance, but the attainment of the technical action value. Thus, while a result of 100 CFU/100 ml previously had no consequences, now this result must trigger action. However, this is not a tightening. Why not? When testing for Legionella, laboratories will now evaluate according to an updated recommendation from the Federal Environmental Agency. This means that several Legionella must be detected in order to report values of 100 CFU/100 ml (or higher). Previously, a single legionella was sufficient. The values are now more reliable.