WIOA – Australian Water Industry Operator Certification Scheme
System Complexity Rating
Under the Certification Framework for Operators within Drinking Water Treatment Systems 2017, the complexity of each drinking water treatment system forms the basis for determining and defining the competency and capability required of the certified operator.
The System Complexity Rating shall be performed by the Drinking Water Supplier and reported where required to the relevant state/territory regulator using a risk-based framework agreed with that regulator.
The Drinking Water Supplier shall ensure that the rating remains current. Where a change in conditions occurs that would be reasonably expected to affect the resultant score, the System Complexity Rating must be resubmitted using the process agreed with the relevant state or territory regulator.
The Drinking Water Supplier shall forward the System Complexity Rating to the Certifying Body (WIOA).
The Certifying Body shall maintain records of the System Complexity Rating and resultant category in relation to its complexity.
Two System Complexity Ratings have been established:
Low Complexity
Will include drinking water systems where no treatment barriers are in place or where disinfection is the only treatment barrier. Fluoridation of water may occur at this level. Skills required by Certified Operators will typically involve chemical dosing, sampling and/or reporting.
High Complexity
Will include drinking water systems that have two or more treatment barriers in place. Fluoridation may also occur. Skills required by Certified Operators will typically involve monitoring, sampling, reporting, chemical dosing and control/optimisation of multiple conventional and/or advanced treatment processes.
Each System Complexity Rating requires certified operators to complete a set of fit for purpose training courses aligned to the treatment processes operated, stipulates an amount of relevant industry experience, requires capability sign off by the employer and includes a requirement to keep skills and knowledge current.
Certification by an independent organisation like WIOA demonstrates that individual operators and the water supplier are committed to the water industry through their professionalism and the attainment of workplace best practice.


