Discussion of “Monochloramine and Legionnaires' disease”

This paper discusses the hypothesis that monochloramine may be beneficial or control of Legionella in plumbing systems. Because monochloramine chlorine penetrates biofilms better than free chlorine, the hypothesis that chloramines are more effective in the biological niche of Legionella is biologically plausible. Investigators from the Centers for Disease Control and Prevention (CDC) presented a study in the September 2000 issue of Journal AWWA concluding that the use of monochloramine for disinfection of municipal water might prevent Legionnaires' disease. These authors suggested that 90 percent of hospital‐acquired outbreaks of Legionnaires' disease associated with drinking water might not have occurred if monochloramine had been used instead of free chlorine for residual disinfection.