legionella testing

Legionella poses a significant risk to workers and the public.  Legionella pneumophila is contracted by inhalation of affected water droplets.  Showers, spray taps, jacuzzies, fountains, humidifiers, vehicle washing equipment and cooling towers can be sources of legionella.

A Legionella risk assessment is particularly important where faculties, shops and offices have been closed for long periods such as during the COVID-19 lockdown.  Legionella bacteria thrive in warm, stagnant water.  The Irish HSE has recently issued warnings about the risk of legionella when reopening facilities.

The consequences of failing to address the risk of legionella can be severe with legal or civil action, destruction of reputations and people requiring hospitalisation.  In some circumstances, death has resulted.  The HSE states that the fatality rate from Legionnaires’ disease is around is 10%. In one recently published High Court case a woman contracted Legionnaire’s disease while using the spa facilities in a five-star hotel in Kerry.  The woman had to be admitted to hospital and was in an induced coma for three weeks.  The woman subsequently sued the hotel and settled. 


Legionella risk assessment

A Legionella risk assessment will help prevent Legionella pneumophila by identifying where the risks are.  Environmental Efficiency carries out Legionella risk assessments in line with guidance document HSG 274 Part 2.  

The risk assessment is performed by checking temperatures of water outlets after running for a specified time.  The hot and cold-water storage facilities are also inspected.  Where equipment produces a spray or mist, for example, cooling towers and jacuzzies or other high-risk areas, samples are also taken. Water samples are sent for analysis to an ISO17025 accredited laboratory.  A report is then written, which constitutes the Legionella risk assessment.


At-risk areas

Legionella bacteria thrive in water that is left stagnant between temperatures of 20 – 45 C. The areas that are most at risk legionella proliferation are:

  • Hot and Cold-water systems
  • HVAC systems
  • Spa pools
  • Cooling Towers
  • Humidifiers
  • Spray wash units
  • Fire suppression systems
  • Hot and cold water tanks


legionella testing

COVID-19 and Legionella Testing

The current Covid-19 pandemic and the addition of the recent warm weather have resulted in conditions that offer legionella a significant opportunity to grow and proliferate within water systems. Businesses that have reduced staff numbers or have temporarily closed will have had water systems used less frequently, therefore creating stagnant areas and dead legs.

With the correct conditions, for example, warm water (20–50oC), the presence of microorganisms and nutrients in the water or materials such as rust, the bacteria can grow and multiply to high levels, which increase the risk of exposure. The bacteria tend to grow in biofilms (slime). Biofilms are likely to form on surfaces where there is low water flow or water is allowed to stagnate. Low or no water flow and stagnation can occur during temporary water system closures.

Legionella Testing in Ireland & UK with Environmental Efficiency

Environmental Efficiency carries out Legionella risk assessments throughout Ireland and the UK.  Please contact us for more information.