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New legislation came into effect on 1 April 2018 relating to the detection and enumeration of Legionella in water.


SGS is ready to analyse water according to ISO standard 11731. ISO 11731 has replaced several existing standards and is applicable to various types of water, such as drinking, industrial, waste, cooling, and surface waters. Specifically, the new NEN-EN-ISO 11731:2017 ‘Water quality – Enumeration of Legionella’ replaces the following standards:

- NEN 6265:2007 ‘Water – Detection and enumeration of Legionella’
- NEN 6266:2014 ‘Water – Explanatory comments on the detection of Legionella according to NEN 6265’
- ISO 11731:1998 ‘Water quality – Detection and enumeration of Legionella’
- ISO 11731-2:2008 ‘Water quality – Detection and enumeration of Legionella – Part 2: Direct membrane filtration method for waters with low bacterial counts’

Dangers of Legionella
When Legionella bacteria are present in water, these can lead to Legionnaires’ disease (a type of pneumonia), especially in people with compromised immune systems. ISO 11731 specifies culture methods for the detection and isolation of Legionella and the estimation of their numbers in the studied water samples.
SGS can help you in this regard as we are ready to analyse your water samples based on ISO 11731.

If you would like to learn more, please don’t hesitate to contact us via email or on +32 3 545 8725 for customised expertise.