Objective To investigate the contamination status and health risk of Legionella pneumophila in the water of public places in Chaoyang District of Beijing, China.

Methods From 2018 to 2019, samples of shower water and the cooling water and condensed water of central air conditioning system were collected from some public places in Chaoyang District. Legionella pneumophila in these samples was detected and classified, and the bacterial concentration was calculated. The health risk of L. pneumophila was evaluated based on bacterial concentration.

Results A total of 651 water samples were collected from 112 public places, and the positive rate of L. pneumophila was 18.6% (121/651), and in which, 41 samples were serotype 1 and 80 samples were serotype 2-14 among the 121 positive samples. There was a significant difference in the positive rate of L. pneumophila among different water samples (χ² = 21.89, P < 0.05), and shower water and cooling water had a significantly higher positive rate than condensed water. There was no significant difference in the positive rate of L. pneumophila in shower water (χ² = 4.03, P >0.05) and in cooling water (χ² = 0.12, P >0.05) from different types of public places. The medium-and high-risk samples containing L. pneumophila type 1 with relatively strong pathogenicity were all collected from cooling water.

Conclusion Legionella pneumophila contamination is observed in the water environment of public places in Chaoyang District. Shower water and cooling water of central air conditioning system have a relatively high detection rate, and cooling water has a relatively high health risk.