To clarify the role of the overall responsible operator (ORO) and the operator-in-charge (OIC).


The owner or operating authority must designate an operator as overall responsible operator for the subsystem. The owner or operating authority, or a person authorized by the owner or operating authority, must also designate one or more operators as operators-in-charge of the subsystem.

These are two different roles, although they can be performed by the same operator as described below.

Role Clarification

As the name suggests, the ORO has overall operational responsibility for the system. To be an ORO, the operator must hold a certificate equal to or higher than the class of the subsystem. An operator with certificate one class lower than the class of the subsystem may assume this responsibility for up to 150 days a year as a back-up when the ORO with the appropriate qualifications is absent or unable to act.

If the system has already designated an overall responsible operator under ss. 23 (1) at the required level who is present and able to act as ORO, the system may not deem an operator at a lower level as ORO under ss. 23 (4). If the ministry finds that a system is designating a lower level operator as an ORO under ss. 23 (4) when the ORO designated under ss. 23 (1) with the required level of certificate(s) is present and able to act as ORO, the ministry will deem this to be a non-compliant event.

There can be only one ORO designated at any given time/shift. If there is more than one operator holding the proper level of certificate, a different ORO can be appointed for different shifts.

The regulations also require the designation of operators-in-charge (OIC). The regulation specifies the duties of an OIC. This person typically makes the day to day operating decisions, and instructs other operators on system procedures. The primary purpose of the operator-in-charge designation is to ensure that operators securing a higher class of certificate have had the experience and responsibility reflected in the duties of an OIC. For example, to secure a Class III or Class IV certificate, the operator must have a specific number of years of experience as an OIC. There can be more than one operator appointed as an OIC at any given time.

The following table lists the difference between the position of an ORO and an OIC
Purpose of positionTo ensure a knowledgeable and experienced person is available at all times to direct other operators on the operations of the system, and to respond immediately and effectively to emergenciesTo ensure that operators who secure a Class III and IV certificate have the specific operating experience gained while an OIC.
Who designates ORO or OICThe owner, (and operating authority if DW).The owner, (and operating authority, or person authorized by the owner or operating authority if DW).
Number that can be designatedOnly one operator can be designated ORO at any given time (per shift, per 24 hour period, etc.).One or more operators can be designated as operators-in-charge at any given time.
Certificate levelORO must have a certificate of the same type and class as or higher than the class of subsystem.Operator must have same type of certificate as subsystem, but it can be a lower class of certificate than the class of subsystem. e.g. treatment type, class I
Operator-in-trainingOperator-in-training cannot be designated ORO.Operator-in-training cannot be designated OIC.
Professional Engineer (without an operator certificate)Professional engineer without a valid certificate cannot be designated an ORO (drinking water).

P. Eng. may be designated as ORO without a valid licence for up to 6 months (wastewater).

Professional engineer or series of professional engineers without a valid certificate can be designated OIC for 180 days in 24 months period (drinking water and wastewater).
Work locationNot required to be on site. ORO must be available and able to act in the event of an operational emergency.

Can be an ORO for more than one subsystem at the same time

Typically works on site given the nature of their responsibilities, but could be off site if process control is remote.

Usually is an OIC for only one subsystem at the same time.

Relationship to operating authorityThe ORO does not need to be an employee of the operating authority. E.g. small water system may enter into a contract with another system for theservice of the other system’s ORO, who would then direct operators employed by the small system on operational matters as needed.Usually is employed by the operating authority.
Role & responsibilitiesThe ORO has overall operational responsibility of a water or sewage system. Typically an ORO:
  • directs operators on operating decisions beyond the knowledge, skill and experience of other operators
  • is expected to be able to respond immediately and effectively to an emergency
  • may or may not be the supervisor or manager
Essentially responsible for the day to day operations of the subsystem. Duties (paraphrased):
  • set operational parameters or direct or instruct other operators on same
  • operate processes safely, in accordance with manuals
  • make adjustments as needed
  • ensure specific records are maintained
  • ensure equipment properly monitored and maintained, and records prepared