Analysis of the distribution of Legionella species in public water systems and investigation of the degree of contamination are the best ways to establish a preemptive management system that can respond quickly in the event of an outbreak. In this study, distribution of Legionella species isolated from public water systems in Busan facilities from 2013 to 2022 was analyzed. Culture and PCR methods were performed for 15,161 environmental water samples collected from public water systems including buildings, hotels, shopping centers, hospitals, public baths, and welfare facilities. Of these samples, a total of 2,156 strains (14.2%) of Legionella species were detected. A total of 1,512 (70.1%) isolates of L. pneumophila were obtained and non-L. pneumophila species were identified in 468 strains (21.7%) with 176 (8.2%) strains showing co-detection. Legionella species were detected in different facilities, including public baths (19.4%), hotels (19.3%), ships (18.6%), buildings (14.2%), hospitals (12.1%), welfare facilities (9.8%), others (9.3%), and shopping centers (9.0%). Detection results for water sources included hot water (19.9%), cooling tower water (15.3%), tank water (11.3%), cool water (8.2%), and others (7.6%). Legionella species were detected mainly in summer, although statistically significant differences in detection among different seasons were not found. High colonization was more frequently detected in water sources from cooling tower water in buildings and hot water in public baths. These results might be useful for preventing and controlling future outbreaks of legionellosis.