Small Drinking Water System Operators

If your business or organization provides unrestricted access to drinking water for the public and your water is not directly from a municipal source, you could be operating a Small Drinking Water System (SDWS). Public Health checks whether small drinking water systems are in compliance with Ontario Regulation 319 Small Drinking Water Systems under the Health Protection and Promotion Act, R.S.O. 1990, c. H.7.

Important information and supporting documentation regarding Small Drinking Water Systems and the regulatory requirements for their operation and maintenance can be found in this Small Drinking Water Systems Operator’s Guide.

Examples of Small Drinking Water Systems may include:

  • A food service establishment
  • A place that operates primarily for the purpose of providing overnight accommodation to the travelling public
  • A seasonal trailer park or campground
  • A marina
  • A church, mosque, synagogue, temple or other place of worship
  • A recreational or athletic facility
  • A place, other than a private residence, where a service club or fraternal organization meets on a regular basis
  • Any place where the general public has access to a washroom, drinking water fountain or shower


Small drinking water systems are inspected based on a risk assessment. Moderate and low risk systems are inspected at least once every four years, and high-risk systems are inspected at least once every two years.

Inspectors look for:

  • Microbiological sampling and testing frequency based on the type of SDWS
  • Water treatment equipment and maintenance
  • Operational checks
  • Records keeping
  • Physical well conditions and environmental factors that may adversely affect water quality
  • Designated operators who are appropriately trained for the safe operation of the drinking water system

Please contact us if you are, or believe you may be, a SDWS and you have not received a site-specific risk assessment by a public health inspector.

Notice of Intent to Supply Water

SDWS owners or operators who are registering for the first time or have undergone construction, installation, alteration, or extensions to the existing water system must notify the Medical Officer of Health before providing water to users. Prior to the seasonal opening of a SDWS (closure for more than 60 days) the owner/operator must have water tested for E. coli and total coliforms, provide the results and notification to Public Health.

Download and complete the Notice to Operate or Reopen a Small Drinking Water System Form

Small Drinking Water System Testing

If you are a SDWS you must perform all drinking water samples through a licensed lab. If you own/operate a SDWS, you are legally required to report any Adverse Water Quality Incidents (AWQI) to Public Health. Complete and submit the Laboratory Services Notification Form before submitting water samples to the lab. For assistance, call 1-800-265-7293 ext. 4753 or email

Reporting Adverse Drinking Water Incidents

Adverse Drinking Water Incidents (AWQI) are adverse drinking water sample results and adverse observations that may impact the quality of water supplied to users. A test or sample that is not within acceptable levels and could cause harm to the health of the users of the system. Total coliform or E. coli would be considered adverse results. Adverse observations may include low disinfection levels in the distribution system, or UV system malfunctioning or turning off due to power failure.

When the lab finds results that are not acceptable, they report to Public Health and the owner/operator of the system immediately by telephone.

The owner/operator must immediately notify Public Health of every adverse observation or test result indicating the system may not be providing safe water. Download and complete the Notice of Adverse Test Results and Issue Resolution (Form # 014-4580-64).

Reporting line and email

Forms and resources

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