Chlorine’s Critical Disinfection Role

Chlorination has played a critical role in protecting Canada’s drinking water supply from waterborne germs for over 100 years.

According to the World Health Organization, the use of chlorine for the disinfection of drinking water is critical for the control of waterborne diseases.×1731.pdf

Alternatives to chlorination for primary disinfection such as ozone or ultraviolet light do not provide residual protection. Chlorine-based disinfectants destroy waterborne pathogens and provide lasting residual protection from re-contamination throughout the distribution system, from treatment plant to the consumer’s tap.

All chemical disinfectants produce low levels of by-products. Chlorination by-products are well studied compared to the by-products of alternative disinfection methods.

According to:

  • Health Canada: “For more than a century, the safety of Canadian drinking water supplies has been greatly improved by the addition of chlorine. Disinfecting our drinking water ensures it is free of the microorganisms that can cause serious and life-threatening diseases, such as cholera and typhoid fever. To this day, chlorine remains the most commonly used drinking water disinfectant, and the disinfectant for which we have the most scientific information…Current scientific data shows that the benefits of chlorinating our drinking water (less disease) are much greater than any health risks from THMs and other by-products.” Ref. It’s Your Health Fact Sheet on Chlorination December 2006 (francais)
  • The World Health Organization: “Disinfection of drinking-water is one of the main achievements of our time in the protection of public health. The use of chlorine for the destruction of microbiological pathogens is essential to protect the public from outbreaks of waterborne disease. Chlorine, as well as other disinfectants, produces a variety of chemical by-products. The risk from the presence of microbial pathogens in drinking-water is estimated to be several orders of magnitude greater than the risk from chlorination by-products. Any efforts to control these by-products must not compromise the microbiological quality of drinking-water.” Ref. Pure & App/. Chem., Vol. 68, No. 9, pp. 1731 -1 735, 1996.
  • Pollution Probe’s Ken Ogilvie: “Chlorinated drinking water – Chlorination has eliminated more deaths than anything else.” Toronto Star 01/01/00 – Survey of Top Environmental Accomplishments