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Drinking Water

We monitor drinking water to ensure a safe, quality, water supply. If there is a threat to clean water, we can issue a Boil-Water Advisory or a Drinking Water Advisory.

Municipal water systems

Waterworks are managed by cities and towns. Ministry of the Environment inspectors ensure that water is treated, disinfected, sampled, and monitored on a regular basis. Any adverse results are reported to us and to the Ministry of the Environment.  If water does not meet the standards of Ontario Regulation 169/03 Ontario Drinking Water Quality standards, we may issue a Boil-Water Advisory or Drinking Water Advisory. All water test results and other water supply information is available to the public. Contact your local municipal office waterworks or public utility for the report. 

Small drinking water systems

Small drinking water systems (SDWS) are inspected by Public Health under Ontario Regulations 318 and 319. There are five classes of SDWS:

  • Small Non-Municipal Non-Residential (e.g., church, motel, B&B, restaurant)
  • Large Non-Municipal Non-Residential (e.g., large resort)
  • Small Municipal Non-Residential (e.g., community hall, sports field/arena)
  • Large Municipal Non-Residential (e.g., airport, large sports complex)
  • Non-Municipal Seasonal Residential (e.g., trailer park, campground)

SDWS documentation and requirements

The Ministry of Health and Long-Term Care provides guidance documents, SDWS fact sheets, and Ontario Regulations.

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

Boil-Water Advisories

The Medical Officer of Health issues a Boil-Water Advisory (BWA) when there is an existing or potential threat to a public drinking water supply. A threat could include poor test results (high microbes) or a break in a water line, flooding, etc. A BWA is lifted when the municipal waterworks department or system operator fixes the problem and has test results to show the water is safe to drink. The BWA may last for any length of time. If you have questions about when the BWA will be lifted, contact your municipality or water system operator. 

When a BWA is lifted, you should receive written confirmation from the MOH indicating the water is once again safe to drink.