The role of Maintenance in the prevention of Legionella’s outbreaks

Legionella is a public health problem and is responsible for “Legionnaires’ Disease”, a type of pneumonia that is contracted by the inhalation of contaminated water vapor droplets (aerosols).


This bacterium is present in aquatic environments, for example, in domestic water systems, jacuzzis and swimming pools, or, in nature, in rivers and lakes. This bacterium naturally appears in plants’ cooling towers, humidifiers, air conditioners, water supply and distribution systems, but only reaches dangerous concentrations in equipment maintenance failures.


The main systems and equipment associated to the development of Legionella are:


  • Cooling systems
  • Hot and cold water building networks
  • Heated water systems for recreational or therapeutic use
  • Acclimatized pools and jacuzzis
  • Thermal facilities
  • Equipment used in respiratory therapy (nebulizers and humidifiers of assisted ventilation systems)


The risks lie in the maintenance and operation of this group of systems, considering that, for an outbreak of this bacterium to occur, the equipment maintenance must have failed. For example, in the case of air conditioning, the lack of maintenance can contribute to air contamination, due to the accumulation of bacteria and harmful substances in filters.


To minimize the proliferation of Legionella, specific preventive maintenance and operation control measures must be adopted. For example, in cooling systems – cooling towers, humidifiers and air conditioning systems – appropriate maintenance programs for the characteristics of the facilities and equipment must be drawn up.


These control and prevention measures, as well as maintenance, cleaning, and disinfection of systems and equipment, are effective solutions to avoid the spread of Legionella.


Maintenance protocols must be created based on a deep understanding of the entire system and equipment, which includes regular inspections, a water control and treatment program, a cleaning and disinfection program for all the facilities and a record of each of these operations. All maintenance and cleaning operations must be recorded in a document or a maintenance management platform.


Another important aspect is monitoring the facilities. It is essential to monitor chlorine levels, the water Ph, the temperature and, currently, it is possible to do so easily and in real time. This way, it is possible to predict when the bacteria may start contamination.


Maintenance and contingency plans are sometimes not prepared with the necessary rigor for this type of equipment, which can inevitably cause outbreaks of Legionella. However, there is already a 2018 law in operation, which establishes the system for disease prevention and control and which points to stricter practices at the maintenance and operation levels of buildings and their equipment.


In fact, the important role of maintenance to prevent the proliferation of Legionella in buildings, equipment and systems is well known.


The impact of lockdown on the origin of Legionella outbreaks


During the pandemic, several plants and companies were forced to close their buildings for some time. Now that they have reopened and returned to their activity, it is essential to implement a rigorous plan of prevention and treatment in the refrigeration ducts, air conditioning and stagnant waters. Otherwise, this equipment will create conditions for the development of Legionella.


Before restarting its operation, procedures for the maintenance and cleaning of the equipment and systems must be implemented in order to prevent water quality problems, namely, the proliferation and dissemination of the bacteria in facilities.


For example, the stagnation of water for prolonged periods in the building’s distribution system, supports the decay of free residual chlorine which can promote the growth of bacteria and can also boost chemical and physical changes in the water.


In the context of a pandemic, often the maintenance is not performed with the due periodicity. The risk of Legionella outbreaks is then quite high, namely through air conditioning, cooling towers, swimming pools, saunas and SPAs.


There were specialists in the field that predicted that these outbreaks would happen as a side effect of the pandemic. Hotels, gyms, plants and other buildings with water and refrigeration systems that were closed during the lockdown, with stagnant water in the pipes, become fertile ground for Legionella, if a strict preventive maintenance plan is not followed before its reopening.


If the entire building has been closed, the cleaning and maintenance of all components for the abovementioned systems must be carried out before reopening.


The failure to comply with maintenance and cleaning plans for systems and equipment is not only detrimental to organizations, but also neglects public health.


Learn how our Valuekeep CMMS can help prevent the outbreak of Legionella.

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