Legionella and drinking water

Today, according to the Italian consolidation act, the employer is required to evaluate the actual risk of Legionella in all workplaces under his responsibility as well as treating these with the mandatory legionella protection. The tests for legionella are in accordance with the “Guidelines for the prevention and control of legionellosis 79/CSR/2015”.

The most correct approach to Legionella prevention is based on the concepts of the World Health Organization for the preparation of a Water Safety Plan:

  • Correct design and construction of technical plants where water is heated and/or nebulised (high hazard plants). Sanitary installations, air conditioning with humidification, cooling systems with evaporation towers or evaporative condensers, plants for the distribution and supply of thermal water, swimming pools and whirlpools are considered such technical plants.
  • adoption of preventive actions (maintenance and, if necessary, disinfection) in order to prevent the multiplication and spread of Legionella in high-risk plants.



Legionella risk assessment is a legal requirement imposed by decree-law 81/08 that refers to the guidelines for prevention and control of legionellosis:

  • Linee guida per la prevenzione ed il controllo della legionellosi” (04.04.2000), issued by the National Institute of Health:  possible intervention strategies to be implemented in hospitals, nursing homes and public structures (hotels, campsites, swimming pools, etc.) are described.
  • Linee Guida recanti indicazioni sulla Legionellosi per i gestori di strutture turistico-ricettive e termali” (document published in the Official Journal No. 28 of 04.02.  2005)
  • In addition, as stated in decree-law 81/2008 and subsequent amendments and supplements, the risk of exposure to Legionella in any working environment requires the implementation of all appropriate safety measures in order to provide the most complete prevention and protection for all persons present, considering that under Chapter X of the aforementioned decree-law 81/2008 Legionella is classified in group 2 among all pathogens.

Security measures have to be adopted after the risk assessment, described in the above-mentioned Chapter X, and shall be implemented according to the provisions of Chapter I (of the before cited decree-law) with reference to the provisions of Arts. 15 and 18. This document is prepared on the basis of the knowledge described in the international scientific publications as well as on the content of guidelines produced at international (WHO), European (EWGLI) and national/regional levels.



All parties who are in different ways involved in the production, distribution and supply of drinking water, have, each for their own area, a share of responsibility with regard to compliance with the parameter values (which have replaced the former maximum permissible concentrations of the Italian Presidential decree 236/88) at the spot where the water – for human use – comes out of the tap.

More precisely, they are bound to ensure that the water quality requirements are fulfilled:

  • The operator, up to the spot of delivery (water meter);
  • The administrator, in case of supply to an apartment building;
  • Every single owner, if each household is connected to its own water meter.



ECO Next has prepared an independent, third-party risk assessment service which allows the certification of a complete risk assessment by analysing the plant and samples of the environment in order to identify critical issues.

The service consists in 3 main steps:

  • Analysis by a qualified Technician in order to evaluate the legionella risk;
  • Sampling and microbiological analysis tap water performed by a qualified laboratory;
  • Preparation of the test report and description of the required measures according to the Legionella Guidelines 2015.


  • Enumeration of Legionella – ISO 11731:2017.
  • culturable micro-organisms at 22°C and 36°C – ISO 6222:1999: Parameter allowing detection of sporogenous, chromogenic, putrefactive etc. microbial species of human or animal origin.
  • Enumeration of Escherichia coli – EN ISO 9308-1:2017: heat-resistant bacterial species whose natural habitat is the human and animal intestine.
  • coliform bacteria – EN ISO 9308-1:2017: bacteria that are widespread in soil, water and the environment in general and some of them are regular hosts in the human and animal intestine.
  • intestinal enterococci – EN ISO 7899-2:2003: habitual host bacteria in the human and animal intestines with a high survival capacity.
  • Pseudomonas aeruginosa – EN ISO 16266:2008: A purely environmental micro-organism and therefore also detectable in drinking water, particularly in stagnant water.

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