The Multi-barrier approach is a key paradigm for ensuring safe drinking water

Drinking water

Drinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...

 in jurisdictions such as Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, elsewhere in Canada, and New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. It is defined as,

An integrated system of procedures, processes and tools that collectively prevent or reduce the contamination of drinking water from source to tap in order to reduce risks to public health.

In Part 2 of his report on the Walkerton tragedy

Walkerton Tragedy

The Walkerton Tragedy is a series of events that accompanied the contamination of the water supply of Walkerton, Ontario, Canada, by E. coli bacteria in May 2000.-Summary:Walkerton is a relatively small community located in Ontario...

, Justice Dennis O'Connor

Dennis O'Connor

Dennis O'Connor may refer to:* Dennis O'Connor * J. Dennis O'Connor, Chancellor of the University of Pittsburgh* Dennis O'Connor * Dennis O'Connor in The Park Is Mine -See also:...

 discusses five elements of the multi-barrier approach:

1. Source water protection
   Source water protection
   Source Water Protection refers to the concept of protecting source water from overuse and contamination....
   
   —Taking action to minimize adverse impacts on source waters reduces the risk from pathogens and chemical pollutants in that water, and can also reduce the degree of treatment required.
2. Robust water treatment
   Water treatment
   Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
   
   —Having treatment trains with more than one step provides redundancy against treatment failure.
3. A secure water supply network
   Water supply network
   A water supply system or water supply network is a system of engineered hydrologic and hydraulic components which provide water supply. A water supply system typically includes:# A drainage basin ;...
   
   —Providing a disinfectant residual to the extreme points of the distribution system protects against water quality degradation and microbial intrusion.
4. Monitoring programs—Monitoring water quality at each of the above points (source, treatment plant, and tap) allows the treatment process to be adjusted to deal with fluctuations in water quality and ensures that the drinking water is safe at the point of human consumption.
5. Prepared responses to adverse conditions—Having response plans (for example, issuing a boil-water advisory) in place provides a final barrier to protect the public if harmful contaminants should make it through the other barriers.

The holistic perspective of the multi-barrier approach also incorporates many players into the goal of keeping drinking water safe. These include managers, researchers, regulators, legislators, and the public.

See also

• Clean Water Act (Ontario)
  Clean Water Act (Ontario)
  The Clean Water Act is a law enacted by the Legislative Assembly of Ontario, Canada. The purpose of this Act is to protect existing and future sources of drinking water....
  
  
• Point of use water treatment
• Source water protection
  Source water protection
  Source Water Protection refers to the concept of protecting source water from overuse and contamination....
  
  
• Water safety plan
  Water safety plan
  A Water safety plan is a plan to ensure the safety of drinking water through the use of a comprehensive risk assessment and risk management approach that encompasses all steps in water supply from catchment to consumer..-Origins:...
  
  
• Water quality
  Water quality
  Water quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
  
  
• Walkerton tragedy
  Walkerton Tragedy
  The Walkerton Tragedy is a series of events that accompanied the contamination of the water supply of Walkerton, Ontario, Canada, by E. coli bacteria in May 2000.-Summary:Walkerton is a relatively small community located in Ontario...
  
  
• Public health
  Public health
  Public health is "the science and art of preventing disease, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, public and private, communities and individuals" . It is concerned with threats to health based on population health...
  
  

Sources

• Health Canada. The Multi-Barrier Approach to Safe Drinking Water. Accessed: 10-Aug-2010.
• Federal-Provincial-Territorial Committee on Drinking Water & Water Quality Task Group (2002). From Source To Tap - The Multi-Barrier Approach To Safe Drinking Water.
• Canadian Council of Ministers of the Environment. Multi-Barrier Approach. Accessed: 10-Aug-2010.
• Hrudey, SE, & Hrudey, EJ (2004).Safe Drinking Water: Lessons from Recent Outbreaks in Affluent Nations, ISBN 9781843390428
• O'Connor, Hon. Dennis R. (2002). Part 2: Report of the Walkerton Inquiry: Strategy for Safe Drinking Water.