If legionella is detected in the drinking water installation above the technical action value, the health authority often requires a risk assessment. This practical example shows how a risk assessment is carried out.
Initial situation
Legionella was detected in a drinking water installation above the technical action value (TMW). The public health department is now requesting a risk assessment or hazard analysis.
Procedure
As part of the risk assessment, the affected drinking water installation is inspected and evaluated. This includes an on-site inspection, the recording of system components such as storage tanks, circulation, risers and tapping points based on technical documents and inspections, as well as the assessment of possible risks of legionella contamination, taking into account the mode of operation, technical condition and general hygiene conditions. This results in an expert opinion with identification of the weak points and specific recommendations for action.
Result
You get clarity: What is the cause, how high is the risk and which measures should be implemented with what priority, i.e. immediately, in the medium term or in the long term?