The Walkerton Incident

Updated on January 10, 2019
E. coli O157.H7
E. coli O157.H7 | Source

On May 24th, 2000, seven people died of whom were seniors and children from a deadly strain of pathogens (E. coli O157.H7 and Campylobacter). More than 2,300 people in the town of Walkerton, Ontario were negatively affected that echoed an unfortunate tragedy in the headlines across Canada. How this happened, the causation, the consequences and the issues leading up to this detrimental event are important in understanding the contributing factors that caused it. The following will cover the events that happened in Walkerton, the type of micro-organisms (pathogens), the role the pathogens played in contaminating the water supply and the ways this incident could have been avoided. The event that took place should be a wake up call to all Canadian citizens and the government to no longer be complacent in the assumption that our drinking water is safe for human life and health without taking full responsibility for it.

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CampylobacterWalkerton's water towerThe E.coli outbreak in Walkerton, Ont., in May 2000 killed 17 people and sickened about 1,500.Source of fecal contaminationclick to enlarge pic
Walkerton's water tower
Walkerton's water tower
The E.coli outbreak in Walkerton, Ont., in May 2000 killed 17 people and sickened about 1,500.
The E.coli outbreak in Walkerton, Ont., in May 2000 killed 17 people and sickened about 1,500.
Source of fecal contamination
Source of fecal contamination
click to enlarge pic
click to enlarge pic

The first sign that something was seriously wrong in Walkerton was in the third week of May leading up to the long weekend when those in the local elementary school and seniors residence started suffering from nausea, stomach pain and severe diarrhea. Many parents and their children started filling the hospital emergency rooms. At the same time, the administrator at the local seniors’ residence instructed the staff of the facility that they were safe to drink the tap water instead of bottled or boiled water because the manager of the Public Utility Commission's report misled them by saying the town’s water was 'ok' to drink. Based on this false report, the Medical Officer of Health was sent on a wild goose chase by believing that it was food contamination that was the source of the illness. A boil water advisory could have been issued on May 19th, but instead it was two days later when the pattern of illness became epidemic. By this time it was obvious that Public Utility Commission’s report was seriously flawed. The big question was, why did the Public Utility knowingly mislead the town of Walkerton into believing that the quality of their drinking water was safe when it was contaminated with potentially deadly strain of pathogens?

The source of E. coli contamination was from municipal Well 5 entering into the Walkerton drinking water distribution system. During the week of May 8th - 12th, 134 mm of rain fell on the town of Walkerton. This was considered a torrential downpour. Because of the heavy rainfall, the primary source of the contamination was the runoff from the manure that was spread on a farm near Well 5 (O’Conner, 2000, p.3). The fecal runoff from the nearby cattle farm impinged on the well and contaminated it. Well 5 drew the contaminated water into the public distribution system from the shallow aquifer that was found to be unmaintained and in an improper location.

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E. coli
E. coli
E. coli

E. coli bacteria live in the intestines of healthy cattle and are passed into their fecal waste. When ingested by humans, a powerful toxin is produced causing bloody diarrhea and can lead to hemolytic-uremic syndrome. The red blood cells in the body are destroyed leading to kidney failure. However, E. coli is a useful organism indicator in testing for human pathogens because it is always found in their faeces. On May 20th, a stool sample was taken from a child who had drank the town's contaminated water supply and tested positive for E. coli 0157:H7 at the local hospital.

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Multi-barrier approach
Multi-barrier approach
Multi-barrier approach

As a Canadian citizen, the ethics, standards and practices used to supply drinking water should be transparent and accountable.

Who do we rely on to implement standards and practices to prevent such disasters?

A preventative rather than a reactive approach to monitoring drinking water would seem to be a more wise direction.

It has been made known that Municipal Well 5 did not have a continuous chlorine dosage or turbidity monitoring system; therefore, two possible preventative systems did not alarm for an appropriate action of whether to increase the chlorine dosage to kill the pathogens or make a decision to send out a boil water advisory. Unfortunately, in Walkerton's case, the boil water advisory was not initiated until many days after the contamination entered the distribution system.

Having code of conduct and safety principles are important and crucial for assuring safe, potable water. Learning from past experiences and dealing with the greater risks first to the lesser last would be a more rational method in risk protection. A preventative approach, instead of a reactive one with some foresight would have been ideal way of preventing the tragedy in Walkerton. An example of foresight would be to implement environmental protection over the regional watersheds to protect the sources of drinking water. If the watersheds are not protected, then the water treatment processes become stressed due to extreme unforeseen conditions put on it.

Well 5 and the Shallow Aquifer

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A well, which became contaminated, was permanently decommissioned and a memorial plaque erected at the site. People gather around the now defunct Well 5 where the original water contamination started during a memorial ceremony in Walkerton, Ont., on Sunday, May 16, 2010. (THE CANADIAN PRESS/Nathan Denette)
A well, which became contaminated, was permanently decommissioned and a memorial plaque erected at the site.
A well, which became contaminated, was permanently decommissioned and a memorial plaque erected at the site. | Source
People gather around the now defunct Well 5 where the original water contamination started during a memorial ceremony in Walkerton, Ont., on Sunday, May 16, 2010. (THE CANADIAN PRESS/Nathan Denette)
People gather around the now defunct Well 5 where the original water contamination started during a memorial ceremony in Walkerton, Ont., on Sunday, May 16, 2010. (THE CANADIAN PRESS/Nathan Denette)

A checklist procedure could respond to questions and describe the type of system that can identify the risk sources and the types of failures that could happen (Hipel, Kilgour, Zhao, 2002, p. 401).

The results of the Walkerton incident can be analyzed to five factors of risk source and failure:

  1. The torrential heavy rain caused the contaminated surface runoff from manure from a nearby cattle farm to contaminate Well 5.
  2. Due to the close proximity of the cattle farm to the well- head, there was a failure to protect the shallow aquifer and the well-head from surface runoff.
  3. The water disinfection systems were not working during the pathogenic outbreak and could not neutralize the harmful bacteria.
  4. The water distribution managers and personnel did not have the proper qualifications or training in their knowledge of E. coli and unwisely chose the cheapest form of water testing due to the lack of financial support from the government.
  5. The laws and regulations pertaining to responsibilities of municipal water were unclear and incomplete.

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A cross-section view of a piece of  water distribution pipe from Walkerton.
A cross-section view of a piece of  water distribution pipe from Walkerton.
A cross-section view of a piece of water distribution pipe from Walkerton.

Walkerton's water distribution system failed on all levels from government, personnel, hardware, finances and the weather.

The public safety of drinking water would be improved by having well trained, committed and dedicated leaders and personnel that can efficiently and effectively face the challenges of providing consistent high-quality drinking water. The more knowledge a water distribution operator has, the more protection the public has. In order to make informed decisions, managers and personnel need practical, scientific, and technical understanding of how to responsibly manage and respond to the challenges of providing safe potable drinking water to the public. If the operators and managers do not know that the greatest risks to drinking water are pathogenic micro-organisms, then the probable risk of waterborne outbreak increases. System operators need to be aware of the risk of sudden changes in water quality due to the extremes conditions put on the environmental from heavy rainfall and flooding. Quick responses to monitoring system alarms can provide preventative measures that the water operator can solve in an efficient manner. If there is no responsibility and dedication to protocol, then incompetence and neglect will only increase the risk. The Public Utility Commission’s operators failed in all preventative measures by not monitoring daily the chlorine concentrations and by forging false data log entries. They did this knowing all along that their practices were unacceptable and unethical.

Number of Cases vs. Age

The Ministry of Environment had a role in regulating and overseeing the treatment, distribution and practices involved in Walkerton’s water system, but failed by not obligating continuous monitoring of the turbidity and chlorine residuals at Well 5. The operators did not have proper training and were ignorant of the importance for continuous monitoring because of the wells vulnerable location. The Ministry of Environment should have known about this and taken the appropriate course of action. They were aware that the operators were not meeting the minimum requirements on several previous occasions, but did not legally enforce proper monitoring.

The provincial (Ontario) government during the Walkerton incident could not legally enforce private laboratories to report excessive levels of contamination to the municipality in an expeditious manner that could have implemented a prompt boil water advisory to the residents of Walkerton. Due to government cutbacks, the government regulated laboratories were replaced by the private sector with no enforceable guidelines until the Walkerton tragedy happened.

The Ministry of Environment went through severe cutbacks of 200 million dollars and 30% reduction in employees by 1999. The government failed to foresee the consequences of their cutbacks to the detriment of human health even though they were forewarned.

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The Walkerton Incident is a lesson to all that providing safe drinking water is a dynamic and complex task of utmost importance. In this case, the philosophy of prevention rather than responsive action with adversity would have been a more rational course of action. When foreseen risks are tackled first from most important to least important, the problems and solutions would be easier to address. The lessons learned from Walkerton are crucial to the evolution of streamlining and improving the water systems that are in place and exposing the ignorance of the bureaucrats.

Providing quality water is an investment that needs the valuable contribution of everyone. It is not something to be taken for granted. The events that took place on May 2000 in Walkerton, Ontario will never be forgotten, especially from families who lost loved ones.

Can we learn from our failures and have the wisdom and hindsight to learn from the past so these types of tragedies do not happen again?

The responsibility seems to fall on each one of us from the government to our own personal duty as citizens to learn, understand and promote importance of maintaining safe drinking water to the public.

A thought to ponder:

If we pay our taxes, support our government and take our influenza shot every year, does that equate to a society free from tragedy?

If not, then how can we make a difference ourselves to better our society and environment around us?


Campell, N. A, Reece, J. B, Taylor, M. R. & Simon, E.J. (2006). Biology Concepts and Connections. San Francisco: Benjamin Cummings.

Hipel, Kilgour & Zhao (2003). Risk Analysis of the Walkerton Drinking Water. Canadian Water Resources Journal, 28 (3), 395-417.

Hrudey, S. E. (2004). Drinking-Water Risk Management Principles For A Total Quality Management Framework. Journal of Toxicology and Environmental Health, Part A, 1555-1565.

O'Connor, D. R. (2001). . Retrieved March 16, 2008 from The Government of Ontario, Ministry Of The Attorney General Web site:

Parr, J. (2005). Local water diversely known: Walkerton Ontario, 2000 and after. Environment and Planning D: Society and Space, 23, 251-271.

© 2011 PlanksandNails

Comments Appreciated

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    • PlanksandNails profile imageAUTHOR


      6 years ago


      It is important to be informed of the potential hazards to drinking water and the necessity to protect the source. Hopefully we can learn from he example of Wakerton that peoples lives and health are at stake, and that drinking water is something that shouldn't be taken for granted.

      Thank-you for your comment.

    • RonDavy profile image


      6 years ago

      It's very dangerous to have a contaminated water source. It's terrible to know this.


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