Occupation Search Results
Licensing Requirements

License Title:



Water Treatment Plant Operator

Responsible for the purification processes of water to be used as public water supplies. Meter chemicals into water based on analytical testing and continuous monitoring to produce a safe, aesthetically pleasing water. Test samples of water throughout the process and record results to assure water quality. Certified operators are required for community (residental) and non-transient, non-community (such as schools and workplaces) public water systems.

Wastewater Treatment Plant Operators

Wastewater Treatment Plant Operators operate mechanical equipment in wastewater treatment facilities in order to remove harmful waste products from water and to render it environmentally acceptable. They maintain pumps, pipes, valves, and processing equipment to move wastewater through collection systems and through various treatment processes. They read and interpret meters and gauges. They also operate chemical-feeding devices, perform laboratory analysis, and keep records of their work. They must be familiar with electricity, mechanics, chemistry, microbiology, hydraulics, and a host of other disciplines.

Wastewater treatment plants are assigned class codes from 1 to 4, with 4 being the highest class and 1 being the lowest class. This plant class is based on a number of factors, including plant design flow, the number of treatment processes, permit effluent limits, and types of industries contributing wastewater. Subclasses are also assigned to wastewater treatment plants that correspond to the processes used at the plant.

What is a Wastewater Certified Operator?

A "certified operator" is an individual who has met the requirements of ch. NR 114, Wis. Adm. Code, and has been issued a certificate by the DNR to operate one or more of the classifications of waterworks or wastewater treatment plants.

NR114 is currently being revised to reflect advancements in treatment technologies along with changes in educational training methods. Please refer to the NR114 Code Revisions Fact Sheet for more information on the proposed changes.

Waterworks Operator Certification

Municipal waterworks operators work at community water systems that are owned by, or serve, a city, town, village, county or other municipality. Also included in this definition are county or state owned public institutions for congregate care or correction. A "certified operator" is an individual who has met the requirements of chapter NR 114 [PDF] Wisconsin Administrative Code, and has been issued a certificate by the DNR to operate one or more of the classifications of waterworks treatment plants.


To become a certified operator, you must pass an exam or exams based on which type of certification you desire. For more information, please see below under "Wastewater Operator" or "Waterworks Operator". Written certification exams are held twice a year at six locations (one in each DNR region) and registration is required. Applications become available on the forms page 2 1/2 months prior to the exam date. The application must be postmarked at least 28 days prior to the scheduled exam date. Any exam applications postmarked after the due date will be returned and the applicant will not be able to participate in the exam.

A score of 75% or higher is a passing score on each exam. Any exam that you pass will be credited to your record. You will receive notice of your exam scores by mail approximately 3-4 weeks after the exam date. The letter sent out after each exam to notify you of the score you received includes a list of missed objectives on the right hand side of the letter. Look up the missed objectives in your study guide for the appropriate subclass to determine what areas of the test you got wrong. Examination papers will not be returned to you.

Applicants who have failed a written exam may apply for re-examination at the next scheduled exam by re-applying and paying exam fees.

revised 4/13

Licensing Authority:
WI Dept of Natural Resources
Integrated Science Services
101 S. Webster Street
PO Box 7921
Madison, WI 53707-7921
(888)936-7463   (608)261-4380 fax


Occupation Profile
WORKnet is moving! We have developed a new site to house the data and resources currently available on WORKnet. Visit Wisconomy.com to start using our new, interactive tools and resources. WORKnet will be transitioned to WisConomy in the fall of 2018. Please email or contact us with any questions.
Wisconsin.gov E-Government Portal
  American Job Center Banner

Home | Contact Us | About Us | Legal | Help | What's New | Site Map
Department of Workforce Development
  The information on this site is updated regularly. The same search run at another time may produce different results.