Highlights
- The main aim of this study was to assess the risk of Legionella colonisation in cooling towers (CT) and evaporative condensers (EC) in Barcelona, Spain.
- Legionella was analysed in 789 samples collected from 127 CT and EC in 46 companies in Catalonia from 2002 to 2019.
- Legionella was isolated in 8.49% of the 789 analysed samples, 22.39% of which were heavily contaminated (with counts higher than 1.0 × 104CFU/l).
- pneumophila was isolated in 82.09% of the samples, with 41.82% belonging to serogroup 1.
- The study showed the importance of risk assessment for improving the control measures aimed at preventing or reducing Legionella populations in CT and EC, thus minimizing potential dangers for public health.