Comparison of rates of isolation of Legionella species from cooling tower water (n = 276) and hot water (n = 228) in facilities such as buildings, hospitals, and public baths. “Other L. pneumophila serogroups*” comprised sg 9 to 15 and L. pneumophila isolates not identified as members of any serogroup. “Other Legionella species**” comprised L. dumoffii, L. rubrilucens, L. spiritensis, and Legionella isolates not identified as members of any known species.