Supervised Persons


Operational checks for chlorine residual and turbidity must be conducted on-site and are done using portable or hand-held testing kits or devices.

These tests must be performed by a certified drinking water operator, water quality analyst or a Trained Person (depending on the category of the system). Individuals who are not certified can also perform chlorine residual and turbidity tests if all of the following conditions are met:

  • they were trained by a certified operator to conduct these tests; and
  • they work under the supervision of a certified operator; and
  • they immediately advise a certified operator of all test results.

Individuals who meet the criteria above are considered “Supervised Persons”.

If you are a Supervised Person working under the supervision of a certified operator, you can conduct these tests in the following types of systems:

  • Municipal:
    • a small municipal residential system
    • a small municipal non-residential system serving a designated facility
    • a large municipal non-residential system serving a designated facility
  • Non-municipal:
    • a small non-municipal non-residential system serving a designated facility
    • a large non-municipal non-residential system serving a designated facility
    • a non-municipal year-round residential system
    • a non-municipal seasonal system serving a designated facility.

Chlorine residual testing in a large municipal residential system must only be performed by persons holding a water treatment, water distribution or water quality analyst certificate.

Certified Operator Supervised Person
  • Receive training from the Certified Operator
  • Document the training you provided
  • Conduct on-site operational checks for chlorine residual and/or turbidity tests after you are properly trained
  • Supervise and give direction to the Supervised Person on when and where to conduct tests
  • Immediately advise the certified operator of all test results
  • Ensure you are available by phone, pager or other means if you need to provide direction to the Supervised Person
  • Seek direction from the certified operator as necessary

Refer to the ministry’s Training Manual for Supervised Persons Conducting Operational Checks for more information about the conditions that must be met for Supervised Persons to conduct chlorine residual or turbidity tests.

For information on the required qualifications to operate, test or sample drinking water systems under the Safe Drinking Water Act, refer to the reference chart available on the Ministry of the Environment and Climate Change website at http://www.ontario.ca/ministry-environment-and-climate-change.