Key Lessons for Public Health Professionals

Since May of 2000, drinking water safety has achieved unprecedented publicity inCanada, yet we need to assure that we are all informed and not misled by media cov-erage. By now, public health practitioners in Canada must know, or at least may believe they know, the story of the Walkerton tragedy. * Fewer may be aware of the details of the North Battleford outbreak of April 2001.† What lessons should public health professionals derive from the findings of the major public inquiries1,2 into these Canadian outbreaks taken together with literature on other outbreaks in the developed world?3 First, the time-honoured framework for drinking water safety, the multi-barrier approach, is more relevant today than ever before. This approach, despite its diverse interpretation over time, offers the most effective framework for achiev-ing drinking water safety. The Walkerton Inquiry Part 2 Report adopted it as the basis for developing a strategy for safe water.4 In addition to ensuring an effective regulatory process and a new commitment to total quality management, the multiple barrier approach was described as involving at least five main elements: • Source protection to keep the raw water as clean as possible to reduce the risk of conta-mination breaching the drinking water system; • Treatment, often involving more than one process, to remove or inactivate contami