A to Z
Data &
Forms &
News &
Licensing &
Rules &
Public Health

Trained and certified operators are necessary to ensure that the systems are managed in a manner that fully protects public health and the environment. 

Water distribution systems are classified according to the population served, and require operators be certified as Distribution Levels 1-4. Treatment plants are classified by assigning points for each unit process and then totaling these points using thePDF DocumentWater Treatment worksheet and require operators be certified as Treatment Levels 1-4.

Operating experience earned at a water treatment plant or distribution system is considered qualifying experience for examinations up to one classification level higher than that of the water system where the applicant gained their experience. In other words, if you have only worked for a Class 2 treatment plant, you may apply for a Level 3 certification but not a Level 4 certification. If you move on to a Class 3 plant, then you must have ½ the qualifying experience (at the Level 3 plant) before applying for a Level 4 certification. 


Certification by reciprocity can be granted for individuals who have a current valid certification in another state or province which has a recognized certification program. The certification is granted where the examination, experience, and education requirements are equivalent to Oregon requirements and is determined on a case by case basis.

Exam Application

Operator certification requires applying for and passing a written exam. Use the application and materials below to apply for certification.  

Levels 1-4 Exam Study I​nformation

​ ​​​​