Adverse Drinking Water Quality Incidents Reports

As part of the day-to-day management of drinking water systems, information is routinely collected and analyzed by municipal and provincial governments. An "adverse water quality incident" is an umbrella term used by the Ontario Ministry of the Environment to refer to any unusual test result obtained from municipal or private water systems. A single adverse water quality incident does not necessarily mean that drinking water from a system is unsafe - it indicates that on at least one occasion, a water quality standard has been exceeded. These range from aesthetic measures, such as taste and smell, to the measurement of the presence of health-related contaminants. As a matter of practice, the ministry ensures that the local Medical Officer of Health (MOH) is aware of any health-related information or incidents. The ministry then works with the MOH and the owner of the system to rectify the situation.

This website only contains information pertaining to systems regulated by Ontario Regulation 170/03, (the Drinking Water Systems Regulation under the Safe Drinking Water Act 2002), that have treatment requirements, serve designated facilities or are within the category "non-municipal year round residential" system. Only health-related adverse water quality incidents involving the detections of E. coli and/or fecal coliforms, or where a Boil Water Advisory, Boil Water Order or Drinking Water Advisory has been issued are reported. Examples of systems that are reported on this site include, but are not limited to, all municipal communal systems serving six or more residences, systems serving designated facilities such as schools, homes for the aged, children’s camps and health care facilities and systems serving permanent mobile home parks. This practice will continue as new reports of adverse water quality incidents are posted as they are identified. The ministry will follow-up on all posted incidents and when an incident has been resolved, the record for the relevant incident will be updated and later removed. Personal information is not provided in accordance with the Freedom of Information and Protection of Privacy Act.

Some categories of water treatment systems in Ontario are presently required by regulation to sample, test and report all adverse results, but are not required to provide treatment until a future date. In addition, private systems serving individual residences, (such as a private well or a system serving five or less private residences), are not regulated by the Drinking Water Systems Regulation unless the system serves a designated facility. Information regarding these systems is not reported on this site. For information regarding these types of systems, please contact the owner of the system or the Medical Officer of Health responsible for the area in which the system is located to determine what drinking water quality information is available.

Contact information for local Medical Officers of Health is available at the following web site:
http://www.health.gov.on.ca/english/public/contact/phu/phuloc_mn.html

If you are having difficulty accessing a document, please contact the Ministry of the Environment at picemail@ene.gov.on.ca or phone the ministry's Public Information Centre at 1- 800-565-4923, in Toronto 416-325-4000 or by mail to the Ministry of the Environment, Public Information Centre, 135 St. Clair Ave. West, 1st Floor, Toronto, ON. M4V 1P5.

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