If the limit value for Legionella of 100CFU per 100ml test water specified in the Drinking Water Regulation is exceeded, the owner or the operator of the building is obliged to commission the necessary measures, e.g. basic disinfection, hazard analysis and remediation plan. Old, sometimes even relatively new sanitary facilities then have to be renovated; pipelines including fittings, boilers, hot water storage tanks and distributors in the entire building have to be adapted or renewed. This renovation according to German DVGW guidelines can take years.
Information about Legionella, diseases and protective measures.