Is disinfectant necessary for safe drinking water?

A silly risk to take since there has never been any credible evidence that byproducts of chlorination pose a cancer risk.

The media release is below.


Is disinfectant necessary for safe drinking water?

A difference has emerged between some Western European countries and the U.S. regarding the use of residual disinfectants to offer safe drinking water. But who is right? In this Perspective, Fernando Rosario-Ortiz et al. compare the different approaches. To avoid microbial contamination, numerous countries including the U.S. and U.K. require the presence of residual disinfectant in drinking water. Yet the presence of a disinfectant can lead to the formation of carcinogenic byproducts, issues with corrosion, and an unappealing taste, the authors note. As well, there is little direct evidence that residual disinfectants have prevented drinking water-related disease outbreaks. A comparison of waterborne outbreak data from the Netherlands, United Kingdom and United States in recent years shows that the Netherlands has the lowest risk of waterborne disease, despite a lack of residual disinfectant use. The Netherlands, the authors note, has replaced more than half its water pipes relatively recently, while the U.S. and U.K. are running on a system comprising “expired” pipes; as pipes age, leaking and reduced pressure increase the chances of bacterial contamination. This may explain the difference among the countries, with leakage as low as 6% in the Netherlands, compared to 25% in the United Kingdom and 16% in the United States. Although more comparative data is needed, the authors note that the European evidence to date suggests that safe water can indeed be delivered without a disinfectant residual, as long as the right infrastructure is in place.

3 thoughts on “Is disinfectant necessary for safe drinking water?”

  1. Every public swimming pool uses a level of chlorination higher than ever found in drinking water as a matter of common practice and proper maintenance. People who use these facilities are, literally, swimming in highly chlorinated water.
    Inevitably a small quantity of this water will be ingested.
    Olympic Athletes in the swimming sports spend many hours on a daily basis in this environment and there has been no evidence [that I am aware of] of a spike in disease in this population group from this prolonged contact.
    If the issue is the delivery system, the pipes and pumping systems, then the relationship between “water-related disease” and system maintenance policies and practices need close examination. With beyond designed expiration date systems different maintenance standards need to be implemented.
    As part of proper public swimming pool maintenance the system is “shocked” at regular intervals by the addition of a higher percentage of sanitizing chemicals. Such a policy is not part of public water distribution systems and so over time harmful bacteria can develop a tolerance to the ambient chemistry.
    In order to reduce the incidence of “water-related disease” from out of date systems either the systems need to be replaced with new physical plant [most especially the distribution piping] or a schedule of regular chemical shocking of the distribution system needs to be instituted.
    Either strategy will involve a certain degree of expense and inconvenience. It is a matter for public policy makers to decide how much expense and how much inconvenience can reasonably be balanced against the potential for disease from these sources.

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