Limited System Operators

Limited systems have limited operational requirements. The system categories below are considered limited systems under Ontario Regulation 170/03 of the Safe Drinking Water Act.

Limited System Categories Examples
Small municipal residential system – groundwater only Residential development with less than 101 private residences
Non-municipal year-round residential system Major residential development, trailer park or camp ground with more than 5 service connections
Large non-municipal non-residential systems that serve a designated facility School, private school, day nursery, children’s camp, children and youth care facility, health/social care facility, health care seniors’ facility, social care facility, delivery agent care facility, university or college
Large municipal non-residential systems that serve a designated facility

There are two types of limited systems:

  • Limited surface water subsystem – where the raw water supply is surface water. It also includes systems that are under the direct influence of surface water, or GUDI systems; and
  • Limited groundwater subsystem – where the raw water is groundwater.

Depending on whether the drinking water source is surface water or groundwater, the person operating that system must hold or be deemed to hold one of the following certificates:

Drinking Water Source Required Certificate(s)
Surface water (or under the influence of surface water) Limited Surface Water Certificate
Water Treatment Certificate (Class 1 – 4)
Groundwater not under the influence of surface water Limited Surface Water certificate
Limited Groundwater Certificate
Water Treatment certificate (Class 1-4)
Water Distribution and Supply Certificate (Class 1- 4)

A person who holds a valid Water Treatment Operator-in-Training (OIT) certificate can operate limited surface water or limited ground water systems. A person who holds a valid Water Distribution and Supply OIT certificate can operate limited groundwater systems.

To get a limited system certificate, you must:

  1. Have an Ontario Secondary School Diploma or equivalent.
  1. Successfully complete the Operation of Small Drinking Water Systems course, available through the Walkerton Clean Water Centre. Visit their Small Systems Zone to register for the correspondence course or online course.
  1. Keep your course certificate as proof of completion.
  1. Apply to write the appropriate Limited System Operator exam using the Examination Registration Form 2130E:
    • Apply for the Limited System Surface Water Certificate exam — if the source of your water is surface water, or groundwater under the influence of surface water
    • Apply for the Limited System Groundwater Certificate exam — if the source of your water is groundwater
    • If you do not hold an Operator-in-Training or Class 1 – 4 certificate, you must verify grade 12 or other training/qualifications considered equivalent to grade 12 with your exam application.
    • Submit your completed application form with payment and the required documentation to the Ontario Water Wastewater Certification Office (OWWCO).
  1. Pass the exam.
  1. Apply for your certificate using the Drinking Water Certificate and Wastewater Licence Application. Submit your completed application form with payment and proof that you completed the Operation of Small Drinking Water Systems course.

A limited system certificate expires every three years. You must renew your certificate to continue operating a drinking water system. To maintain your certificate, you need to meet all of the following criteria and apply to renew your certificate before it expires:

  1. Complete the mandatory renewal course.
    • The mandatory renewal course: Safe Drinking Water Operator Essentials is offered through the Walkerton Clean Water Centre (WCWC). You can complete it by correspondence or attend the course in person.
    • Visit WCWC for course offerings and to find out how to register.
  1. Complete 21 hours of Director approved continuing education.
    • The mandatory renewal course counts as 7 hours of the continuing education requirement.
    • Review the list of Director approved courses. One Continuing Education Unit (CEU) is equal to 10 hours of training.
    • Contact the training providers on the list to find out when and where courses are being offered and get yourself registered.
    • Keep all your training records. You will need to submit proof of training when you apply to renew your certificate.
  1. Complete 39 hours of on-the-job practical training.
    • In addition to accepted activities to renew Class 1 – 4 certificates, the ministry may accept the following as on-the-job practical training for limited systems certificates:
    • reviewing inspection results with a water inspector;
    • viewing related videos; and
    • reading system specific operational manuals/instructions/emergency procedures (maximum of 9 hours per certificate cycle will be accepted).
    • Refer to the Guide to Drinking Water Operator Training Requirements for a complete list of acceptable on-the-job training activities.
  1. Meet operational experience requirements.
    • You must have at least 3 months experience in the previous 36 months of working as an operator in a subsystem, or experience that the Director considers as related.
  1. Apply to renew your certificate at least one month before it expires.

For additional guidance go to