Can Legionella survive in chlorinated water?
Legionella has been isolated from chlorine treated water. The levels of Legionella that elude the water treatment process are essentially undetectable. When this water travels through the system and loses much of the chlorine residual, either from retention time or warm temperatures in water distribution systems, Legionella can then be cultured. The colonization rate for large buildings is 20-70%, depending on the geographic region. Residential water systems can also harbor Legionella. It is very interesting to learn from The Lancet Infectious Disease, June 2003 article that virtually all outbreaks have been linked to potable water, and that showering is not a mode of transmission (except perhaps for high risk patients?). Showering is allowed even for high-risk patients. Highly-immunosuppressed patients and COPD (emphysema) patients should drink bottled water or boiled water that has been cooled, but this is optional. If the percent of distal water sites is < 30%, we do not prohibit sh
