Drinking Water System Components-Microbial Growth

Legionella incidence is on the rise in Canada and across North America. In Canada, the number of reported cases of Legionnaires’ Disease is generally less than 100 per year although the actual number of cases is suspected to be much higher as many patients are often treated for symptoms and not tested for Legionella. The CDC recently reported a record number of Legionnaires' diseases cases - 9,984 in 2018, an eightfold increase over 2000. In its August 2019 report called Management of Legionella in Water Systems, the National Academies of Sciences, Engineering and Medicine (NASEM) conservatively estimated the actual number of Legionnaires' cases each year in United States is between 52,000 and 70,000. The report points out that the NSF/ANSI/CAN 61 standard does not address the microbial growth potential of materials in contact with water and recommended that "New NSF/ANSI/CAN standards regarding microbial growth potential of materials are needed so that water utilities, plumbers, and building contractors can include Legionella control when making decisions about pipe material usage."