Jerry Schnoor, Allen S. Henry Chair in Engineering and professor of civil and environmental engineering and occupational and environmental health, recently co-authored an article on safe drinking water in Science magazine.
The article, titled "How do you like your tap water?", compared water safety techniques in the United States and Europe, arguing that drinking water may not need to contain a residual disinfectant to be safe for consumers. While the United States requires residual disinfectants in order to prevent microbial waterborne pathogens, little evidence exists that these disinfectants have prevented outbreaks of waterborne disease.
In some European countries, drinking water can be delivered to consumers without a residual disinfectant as long as there is adequate source protection, treatment, and maintenance of the distribution system to prevent growth of pathogenic bacteria and additional contamination events. In the Netherlands, a country which requires no residual disinfectants, outbreaks of waterborne disease per 1000 population in the last few years was as low as 0.59 compared to 2.79 in the United States.
Another issue for consideration is the distribution system age and composition, which caused the recent public health emergency of lead contamination in Flint, Michigan.
A full understanding of the long-term properties of water distribution systems will require comparative data on water quality, disease outbreaks, and distribution system failures from all approaches used to produce safe drinking water.
Schnoor’s co-authors were Fernando Rosario-Ortiz, Joan Rose, Vanessa Speight, and Urs von Gunten.