Moist environments and aqueous solutions serve as reservoirs for waterborne pathogens. Under favorable conditions (i.e., warm temperature and a source of nutrients) many microorganisms actively proliferate; or remain for long periods in highly stable, noninfectious forms. From a contaminated water source, pathogens can be transmitted by direct contact with water, ingestion or aspiration of water, indirect-contact transmission (e.g., improperly reprocessed devices), and inhalation of aerosols.1

Direct contact with contaminated water, ingestion of contaminated water, and indirect-contact transmission are commonly associated with infections caused by Pseudomonas aeruginosa and other gram-negative bacteria, and nontuberculous mycobacteria (NTM) commonly found in potable water.1,2 Aspiration of water or water aerosols generated from water sources contaminated with Legionella spp. often serve as the vehicle for introducing Legionellae into the respiratory tract.1,2