Public Drinking Water


How can I be certain the water from a public water system is safe?

Public Health Inspectors and Ministry of Environment Inspectors monitor public drinking water systems to ensure a safe water supply. If we find that a water system cannot provide safe water the system operator or public health will issue a boil water or drinking water advisory to protect the health of the system users. If your residence is connected to a private communal water system that does not meet the small drinking water system criteria you can contact the system operator to determine what level of monitoring is carried out.


Municipal Water Systems

Municipal water systems are operated by the city or town they service. The water system operators follow stringent procedures for monitoring the water quality as set out by Ministry of the Environment standards. The Ministry of the Environment inspectors monitor the waterworks to ensure the water is treated, disinfected, sampled, and monitored as required. Any adverse test results are reported to Public Health and to the Ministry of the Environment. If water does not meet the standards of Ontario Regulation 169/03 Ontario Drinking Water Quality standards a Boil-Water or Drinking Water Advisory may be issued. You can obtain test results and other information from the municipality that operates the water system by contacting your local municipal office; some municipalities have reports available on their website. 


Walkerton Outbreak

Reports, news releases, and fact sheets related to the Walkerton E. Coli outbreak of May 2000 in which seven died and thousands became ill.


Small Drinking Water Systems (SDWS)

Small drinking water systems are regulated under Ontario SDWS Regulation 319. Public health inspectors (PHI) conduct a site-specific risk assessment for every small drinking water system. Based on the assessment, they will determine what owners and operators must do to keep their drinking water safe, and will issue a directive for the system. The directive may include requirements for water testing, treatment requirements or training. The water system is then monitored by Public Health to ensure all requirements are being met. Any adverse test results are reported to Public Health. Boil Water or Drinking Water advisories may be issued by the operator or Public Health to protect the health of the water system users.

If your business or premises makes drinking water available to the public* and you do not get your drinking water from a municipal drinking water system, you may be an owner or operator of a small drinking water system. If you are not sure whether your system is affected, contact the Grey Bruce Health Unit.

* systems serving designated facilities such as children’s camps, health care facilities, social care facilities, schools, universities, colleges or other degree-granting institutions are not considered small drinking water systems and remain under MOE regulation.


SDWS Resources, Documentation, and Requirements

Please see the Ministry of Health and Long-Term Care for SDWS Regulations, guidance documents, and fact sheets.

The Government of Ontario Central Forms Site provides the following SDWS forms:

Other Resources


Boil Water Advisories, Orders, and Drinking Water Advisories

Boil Water Advisories, Orders, and Drinking Water Advisories are public notices issued when conditions indicate that public drinking water is not safe for use. The type of notice issued will depend upon the problem with the drinking water. The notice will indicate whether you can continue to use the water after appropriate treatment or if an alternative source of water is required.


Fact Sheets


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