Guidelines for drinking-water quality, 4th edition, incorporating the 1st addendum

Overview

 

The fourth edition of the World Health Organization’s (WHO) Guidelines for drinking-water quality (GDWQ) builds on over 50 years of guidance by WHO on drinking-water quality, which has formed an authoritative basis for the setting of national regulations and standards for water safety in support of public health.

It is the product of significant revisions to clarify and elaborate on ways of implementing its recommendations of contextual hazard identification and risk management, through the establishment of health-based targets, catchment-to-consumer water safety plans and independent surveillance.

This first addendum updates the fourth edition. Updates reflect new evidence and further, provides additional explanations to support better understanding and application of the guidance.

Updates

Chemical background documents for bentazone, chromium, iodine, microcystins, tetrachloroethene and trichloroethene have been revised. New chemical background documents have been prepared for anatoxin-a and analogues, cylindrospermopsins and saxitoxins while a chemical background document for organotins has been developed, to replace the background document on dialkyltins. The recommendations in these background documents, including any changes in guideline values, supercede the recommendations in the GDWQ, 4^th edition, incorporating the 1^st addendum. The background documents can be accessed through the list of chemical hazards considered in the WHO GDWQ.

The GDWQ, 4^th edition, incorporating the 2^nd addendum, will be published by mid-2021 to reflect, inter alia, key information in these background documents.