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Current information on the obligation to report large facilities for heating drinking water, the obligation to inspect for legionella as well as sample points (quantity and site).


The following information is also available to download from our download area, under the customer information sheets header.

Reporting obligation/Inspection obligation 

On 11 May 2011, the German Ministry of Health announced an amendment to the Drinking Water Ordinance (TrinkwV) in the Federal Law Gazette in the Bundesrat. The amended regulation came into force on 1 November 2011. Since then, large facilities for heating drinking water in residential buildings must also now be subjected to annual representative sampling for legionella. Previously, this only applied to large facilities for preparing drinking water for the public. Furthermore, there is now an obligation to register large facilities for heating drinking water with the health authority. The large facilities subject to obligatory inspections are those hot water installations with more than 400 litres storage capacity and/or hot water pipes with more than 3 litres’ content in each pipe between the water heating system and the point of withdrawal. Any possible circulation pipe is not taken into account in these calculations. Property owners and landlords, but also people managing buildings of residential flats, are now obliged to actively implement the new regulations.

Technical measure values

The amended TrinkwV now includes a technical measure value for legionella. This is 100CFUs/100ml. Drinking water installations that meet recognised technological standards usually maintain this value. If, however, this value is reached or exceeded, this is generally a reliable indication that there are avoidable technical faults in either the drinking water installation or how it is operated. This also reflects the classification of the parameter in appendix 3 of the indicator parameters. If required, the cause must be dealt with by an on-site inspection of the affected drinking water installation, in order to assess the danger and also to check whether generally recognised technological standards have been applied.

Sample points

With regard to adherence to the technical measure value, it is made clear that a random sample is not sufficient to be able to establish whether there is a possible legionella contamination. Section 14 of the TrinkwV stipulates that systemic inspections must be made at multiple representative sampling points. Furthermore, the type of sampling is also set out.

The sampling scheme as described in DVGW data sheet W 551 must be used. According to this, the water heater’s outlet, the circulation’s return flow and every end pipe must be sampled and analysed. The business operator must also ensure that appropriate sampling points are fitted with suitable means of sample withdrawal (taps) in accordance with generally recognised technological standards. Furthermore, you must not extract the water samples yourself.

Inspection centre

The inspection centre contracted for taking and analysing the samples must be listed in a current publicly available state list , in accordance with section 15, paragraph 4, and must meet the criteria set out there. This approval then applies across Germany. The Institut Kirchhoff Berlin GmbH is accredited to DIN EN ISO/IEC 17025:2005 and named in the list, in accordance with section 15, paragraph 4 of the TrinkwV. Not only can the institute determine legionella, but also carry out expert sampling and provide expert advice.

Findings of legionella 

The client must notify the respective health authority of the results of legionella examinations within two weeks of receiving them. Furthermore, affected tenants must also be informed immediately in a suitable form (for example, a sign).

Sanctions for breaches of the Drinking Water Ordinance

Whoever intentionally or negligently breaches the reporting, inspection, recording or informational requirements, or who does not properly maintain or operate his or her drinking water supply system, commits an offence under section 25 of the TrinkwV. Furthermore, the intentional or negligent provision of microbiologially or chemically contaminated drinking water also represents a criminal offence under section 24 of the TrinkwV.

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