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WHO issues revised drinking water guidelines to help prevent water-related outbreaks and disease

African child drinking from tap

Ensuring drinking water is safe is a challenge in every part of the world, from water piped into people's homes, to rural wells and water provided to refugee camps in an emergency. Contamination of drinking water is too often detected only after a health crisis, when people have fallen ill or died as a result of drinking unsafe water. Today, WHO is releasing new recommendations which will help pre-empt drinking water contamination.

WHO advises national and local drinking water regulators, and the enterprises and organizations which actually provide drinking water to five billion people around the world, that the challenge of providing safe drinking water is growing. WHO's updated Guidelines for Drinking-water Quality (GDWQ) will help regulators and water service providers the world over maintain and improve the quality of their drinking water.

“This is an extremely important change in orientation from a public health point of view. The revised Guidelines will allow public health management to focus on prevention of microbial and chemical contamination of water supplies,” said Dr Kerstin Leitner, WHO Assistant Director-General for Sustainable Development and Healthy Environments. "And they have as much applicability whether we are talking about an urban drinking water system in North America, or protected wells in the developing world. This new approach exhorts all parties working on drinking water provision and control to act in such a way that outbreaks of water-borne diseases can be further reduced."

Traditionally, drinking water regulations have emphasised testing water samples for levels of chemical and biological contaminants. Relying on this approach means that problems are detected long after water is consumed - a remedial rather than preventive approach.

Outbreaks due to microbes in drinking water can affect hundreds of thousands of people. In recent years, communities large and small in some of the world's most developed countries have been affected by contaminated drinking water. In Canada, disease outbreaks due to E.coli O157 and Campylobacter, or Cryptosporidium in the United States, Japan and France as recently as this month, show what can happen if vigilance is not maintained.

The Hepatitis E outbreak currently sweeping through internally-displaced-persons camps in Darfur, Sudan and refugee camps in neighbouring Chad is one example of how water-borne disease affects poor and disadvantaged populations. These new guidelines on drinking-water quality include new guidance on their application in specific settings such as emergencies and disasters.

The updated Guidelines represent a paradigm shift in advice on how to manage the provision of drinking water, both in the developed and developing world, in large urban settings and in the rural areas or villages. Henceforth, according to the revised GDWQ, the recommended approach for regulators and operators is to manage drinking water quality in a holistic, systematic fashion from source to tap. This includes ensuring water reservoirs, or, local wells, aren't at risk of contamination from human and animal waste, to checking basics like the regular changing of water filters.

"This third edition of the WHO Guidelines for Drinking-water Quality is the most significant water-related public health development since the introduction of chlorine. The Guidelines' requirement for drinking water safety plans should be incorporated in regulations across the world," says Dr Michael Rouse, President of the International Water Association (IWA).

The new edition has reviewed and revised the recommended values for chemical limits in drinking water in line with the latest scientific evidence. The GDWQ reconfirm guideline values for over 100 chemicals. Because routine monitoring for all of the chemicals is not possible, the guidelines set out practical approaches to 'rule out' some chemicals and to prioritize others using readily available information.

In the accompanying annex, examples from around the world show how much more of an impact prevention rather than response can have in maintaining drinking-water quality.

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For more information contact:

Mr Gregory Hartl
Telephone: +41 (22) 791 4458
Mobile phone: +41 (79) 203 6715
E-mail: hartlg@who.int

WHO Guidelines for drinking-water quality