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Environmental and Workplace Health

The Multi-Barrier Approach to Safe Drinking Water

Help on accessing alternative formats, such as Portable Document Format (PDF), Microsoft Word and PowerPoint (PPT) files, can be obtained in the alternate format help section.

The key to ensuring clean, safe and reliable drinking water is to understand the drinking water supply from the source all the way to the consumer's tap. This knowledge includes understanding the general characteristics of the water and the land surrounding the water source, as well as mapping all the real and potential threats to the water quality. These threats can be natural, such as seasonal droughts or flooding, or created by human activity, such as agriculture, industrial practices, or recreational activities in the watershed. Threats can also arise in the treatment plant or distribution system thanks to operational breakdowns or aging infrastructure.

The multi-barrier approach takes all of these threats into account and makes sure there are "barriers" in place to either eliminate them or minimize their impact. It includes selecting the best available source (e.g., lake, river, aquifer) and protecting it from contamination, using effective water treatment, and preventing water quality deterioration in the distribution system.

The approach recognizes that while each individual barrier may be not be able to completely remove or prevent contamination, and therefore protect public health, together the barriers work to provide greater assurance that the water will be safe to drink over the long term.

What information is available

Several guidance documents have been developed in collaboration with stakeholders and partners to describe the approach and its implementation.

Intake to tap (December 2001)
This document was developed by a working group of the Federal-Provincial-Territorial Committee on Drinking Water. It considers the factors that affect drinking water quality from the intake to the tap, while recognizing that source water protection is an integral part of the process. It identifies key elements in a comprehensive drinking water program and sets out best management practices for drinking water purveyors. The guidance is designed specifically for the water industry (public and private), including managers and practitioners responsible for ensuring safe drinking water, whether the supply is public or private, large or small, urban or rural.
From Source to Tap: The Multi-barrier approach to Safe Drinking Water (May 2002)
This short position paper was developed jointly by the Federal-Provincial-Territorial Committee on Drinking Water and the Canadian Council of Ministers of the Environment Water Quality Task Group. It builds upon the information in the Intake to Tap document (see above) to include strategies for source water protection. This paper was prepared for a general audience (such as governments, citizens, and interested stakeholders) to communicate the concept of a multi-barrier approach to drinking water protection.
Next link will take you to another Web site From Source to Tap: Guidance on the Multi-barrier Approach to Safe Drinking Water (June 2004) (PDF Version - 247K)
This technical guidance document is a companion document to the May 2002 position paper, and was also produced jointly by the Federal-Provincial-Territorial Committee on Drinking Water and the Canadian Council of Ministers of the Environment Water Quality Task Group. The document provides in-depth guidance to drinking water system owners and operators on how to apply the concept of the multi-barrier approach to Canadian drinking water supplies.
Guidance for Providing Safe Drinking Water in Areas of Federal Jurisdiction - Version 2 (May, 2013)
This guidance document has been developed by the Interdepartmental Working Group on Drinking Water, which consists of 17 federal departments who have responsibilities for producing and/or providing clean, safe and reliable drinking water in areas of federal jurisdiction.  The purpose of this document is to give clear, consistent guidance on how to implement the Guidelines for Canadian Drinking Water Quality. This guidance is directed to federal civil servants or other responsible authorities whose jobs relate, either directly or indirectly, to ensuring the safety of drinking water on federal lands, in federal facilities and/or in First Nations communities. It is written for employees who make decisions at the policy and management levels, as well as for those who run drinking water systems on a day-to-day basis.

When printing a hard copy of this document from Health Canada's web site, it is recommended that the Summary of Guidelines for Canadian Drinking Water also be printed, as it is updated on a regular basis.