Remain effectively        

in the flow

Project Reports

Rinsing and disinfection measures in the area of building installation:


- successful against legionella pneumophila,
pseudomonas aeruginosa, general bacterial contamination
(E.coli, coliform germs, increased CFU).

In this context, read our
Project Reports

+ + +

Who is affected by the new [German] Potable Water Ordinance?

House owners, landlords and housing management companies.
The water supply company is responsible for the potable water quality up to the transfer point, usually the water meter. From this point onwards, the quality depends on the internal building system and is the responsibility of the owner / operator of the system.

In line with Section 13 of the new Potable Water Ordinance, the public health authority responsible must be notified regarding every hot water supply system.

Here you will find a notification form for download

With the Potable Water Ordinance, special obligations to carry out analyses came into effect from 1 November 2011. In accordance with Section 14, Paragraph 3 of the Potable Water Ordinance, owners, owner associations, building associations and house management companies operating on their behalf are now under obligation to have their potable water installations analysed with regard to legionella by a certified company once a year (see Service / Sequence / Costs). This analysis is carried out in line with the German Association for Gas and Water work sheet W 551 and concerns systems for potable water heating with a volume of at least 400 litres or hot water pipes with a volume of at least 3 litres between the potable water heater and the outlet, which means it covers practically all apartment buildings. The number of representative sampling points is based on the generally recognised principles of engineering as described in the German Association for Gas and Water work sheet.

Where does sampling take place?

As a rule, the water at the exit point of the hot water heater (hot water feed pipe) and at the end of the circulation pipe (hot water return pipe) is to be sampled before it re-enters the hot water heater. Moreover, the water of every ascending pipe is to be analysed: at the outlet furthest away from the hot water heater and at the outlet that is used the least.

Sampling taps complying with German Association for Gas and Water, initial technical requirement Probenahmehahn

Where not already present, flame-resistant sampling taps (sampling taps complying with German Association for Gas and Water) are to be fitted by a plumber at the exit point and entry point of the hot water heater; these must be suitable for micro-biological sampling.
For this reason, please contact your house plumber. A suitable alternative to flaming the sampling taps is CARELA® fix & des, a ready-to-use disinfectant spray that can be used to disinfect sampling points adequately and quickly.

Sampling complying with DIN EN ISO 19458

Sampling is carried out in compliance with DIN EN ISO 19458, which means that the sampling may only be carried out by a trained sampler. The analysis for legionella may only be carried out by listed laboratories with the appropriate statutory authorisation.

Duty to provide notification where technical  measure value is exceeded (> 100 CFU / ml)

Following the sampling and analysis of the potable water, a copy of the record of the analysis results must be sent to the public health authority responsible within two weeks of completion of the analysis. If the so-called technical measure value is exceeded (legionella concentrations of 100 or more CFU / 100 ml; CFU = colony-forming units), immediate notification is required (Sections 15 and 16 of the Potable Water Ordinance).
The public health authority can also be notified by the laboratory if specified by the public health authority responsible and you have consented to this notification.

The tenants of apartment buildings must also be provided with information material regarding the potable water quality based on the results of the analysis once a year (see Section 21, Paragraph 1 of the Potable Water Ordinance).


Risk analysis - aim and scope

The aim of the risk analysis is to systematically identify the deficiencies or events that led to contamination of the potable water system (e.g. with legionella). Based on this, the risks to health can be estimated and assessed, and the corresponding measures can be derived and prioritised.

The risk analysis is commissioned by the operator. The public health authority only checks whether the operator complies with their obligations. When selecting the service provider, it is important to pay close attention to the qualification of the technical hygiene expert for risk analyses.

Risk analyses can be commissioned here: risk analyses