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Wastewater operator certification

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 wastewater treatment plants.

Wisconsin Administration Code NR114 was recently revised to reflect advancements in treatment technologies along with changes in educational training methods. The effective date for these changes was July 1, 2015. See the NR 114 Revisions Webpage for more information.


In order to become a certified wastewater treatment plant operator, you must pass both the basic general wastewater exam and at least one basic subclass exam. The subclass exam(s) which you should take is dependent upon the processes at the treatment plant at which you work, or would like to work.

Study guides are a valuable tool to help prepare for exams. There are also several courses, listed on our training calendar, that help prepare for exams. Prior education or training is not required before taking the exams, however, some classroom or online training is recommended.


Wastewater treatment plants are assigned a basic or advanced classification rating. Subclasses are also assigned to wastewater treatment plants that correspond to the processes used at the plant. Each plant must have a designated operator-in-charge certified at the plant class level and in the same subclasses as the processes used at the plant.

Category Subclass Letter Subclass Name Description
Biological Treatment A1 Suspended Growth Processes Activated Sludge and variants
A2 Attached Growth Processes Trickling filters, RBCs and biotowers
A3 Recirculating Media Filters
A4 Ponds, Lagoons, and Natural Systems
A5 Anaerobic Treatment of Liquid Waste High strength liquid waste treatment system
Solids Separation B Solids Separation Clarifiers, membranes, filters, tertiary phosphorus removal, etc.
Solids Treatment C Biological Solids/Sludge Handling, Processing, and Re-use Aerobic and anaerobic digestion, thickening, dewatering, land application
Nutrient Removal P Total Phosphorus
N Total Nitrogen
Disinfection D Disinfection Chlorination, ultraviolet radiation, ozone
Laboratory L Laboratory Registered or certified on-site laboratories
Special U Unique Treatment Systems Unique, special treatment plants that use biological, chemical or physical methods
Collection System SS Sanitary Sewage Collection System


The requirements for wastewater operator certification for each level are:

  • Operator-in-Training (OIT): Pass Basic General Wastewater Exam* and Basic Subclass Exam
  • Basic: One year of subclass specific experience
  • Advanced: Obtain 10 advanced points and submit an advanced certification application (see the Advanced Certification webpage for more info)

*Note: The Basic General Wastewater Exam is not required for the Collection System certification or the Special U certification.

Experience is documented on the Wastewater Operator Experience Form available on the Forms page. One year of experience is based on full-time employment at a treatment plant or 1,000 hours of cumulative experience, over a minimum of twelve months, for part-time operators.


If you have a current wastewater and/or waterworks certificate from another state and are interested in applying for reciprocity to Wisconsin's operator certification program, application materials are available on the Forms page. Questions regarding reciprocity can be directed to the statewide operator certification coordinator, Lisa Bushby, 608-266-0498.

Study guides

Given the significant time and effort needed to revise study guides according to the new subclasses that became effective July 1, 2015 under Wisc. Adm. Code NR 114, study guides will be released and available in phases as given below. Only exams for which study guides are available will be given on the exam date. Note: These are tentative dates.

For questions about the study guides and their availability, contact Jack Saltes, Wastewater Operations Engineer at or 608-264-6045.

Available now

Available by February 1, 2016 (for May 2016 exam date)

  • A2 - Biological Treatment - Attached Growth Processes
  • B - Solids Separation
  • C - Biological Solids/Sludge- Handling, Processing and Reuse

Available by February 1, 2017 (for May 2017 exam date)

  • N - Nutrient Removal - Total Nitrogen
  • A5 - Anaerobic Treatment of Liquid Waste

Available by August 1, 2017 (for November 2017 exam date)

  • Sanitary Sewer Collection System

In addition to the study guides, wastewater operators can borrow technical manuals from the UW Water Library [exit DNR].

Continuing ed

Certification must be renewed every three years. This continuing education requirement is designed to help operators keep current on new requirements and technical innovations. Continuing education also helps operators acquire additional knowledge and skills.

  • Operator-in-training and basic level operators require 18 hours of continuing education.
  • Advanced level operators require 24 hours of continuing education

Credits must be earned within the three year license period. For example: If November 1, 2015 is the expiration date of the certification, continuing education credits must be earned between November 1, 2012 and November 1, 2015 to be valid for renewal.

The continuing education must be relevant towards the operation of a wastewater treatment plant. Continuing education credits may be obtained in a number of different ways including attendance at professional organization meetings or conferences, wastewater related courses (such as those offered at technical schools, colleges, or non-profit organizations), in-house training, or online wastewater courses. Please refer to our Training Calendar for an extensive list of applicable courses and trainings.

Credit for courses or training is determined by the following criteria:

  1. Each hour spent in course learning constitutes one credit hour of continuing education credit (minus time spent for registration, breaks and lunch).
  2. A maximum of six hours health and safety related training may be used per renewal period. Examples of health and safety related training include first aid/CPR, confined space entry, excavation safety, personal protective equipment, Hazwoper, RCRA, and bloodborne pathogens.

If an operator takes a training that was not pre-approved, but is relevant towards wastewater operations, the operator may complete the Operator Training Report Form [PDF] to document the training. Proof of attendance documentation must be attached to the Training Report Form.


Operator certifications come up for renewal every three years. DNR sends courtesy renewal reminder letters to operators six weeks before their certification expiration date. It is important for operators to keep their address current by notifying their regional coordinator of any changes. The letter serves as a courtesy reminder only; it is the operator's responsibility to keep track of their certification expiration date. When the operator is ready to renew, they should mail in the courtesy reminder letter, their continuing education documentation, and the $45 renewal fee to:

Operator Certification Program - SS/7
PO Box 7921
Madison WI 53707-7921

The renewal materials must be postmarked by the expiration date on the certificate (there is no grace period). Any renewal postmarked after the expiration date should also include the $25 late penalty fee.

Once a certification expires, an operator has one year from their expiration date to reinstate their lapsed certification. An operator is NOT considered a certified operator during this lapse of certification. If a certification is not renewed within that one year time period, the operator will need to re-take the exams as a new operator.

Adv Cert

10 points total is required to obtain advanced level certification. At least 4 of the points must be obtained through hands on experience; the operator must have at least 4 years of hands on experience in order to apply for advanced certification. A maximum of 6 years of hands-on experience can be used towards points. An Advanced Wastewater Treatment Plant Operator Certification Application [PDF] must be submitted, along with the $100 application fee.

Type Point Method Points Minimum Hours
Experience 4 years hands-on 4 4,000
5 years hands-on 5 5,000
6 years hands-on 6 6,000
Degree Undergrad or Graduate Degree 6 At least 240 hours wastewater related courses
Water/Wastewater Associates Degree 6 N/A
Apprenticeship Completion of State Approved Apprenticeship Program 6 N/A
Exam 100 Question Multiple Choice Exam 4 N/A
Advanced Coursework Pre-approved by the DNR and on list of approved courses 2 80
1.5 60
1 40
0.5 20

Advanced coursework must be from the approved advanced coursework list [PDF] in order to be eligible for advanced certification points. This list is updated September 1st of every year.

For questions on the advanced certification application process, please contact Danielle Luke, wastewater support specialist, 608-266-9239,



Where can I obtain the application to take an exam?
Applications are available on the forms and applications website in mid-February for the May exam day and in mid-August for the November exam day.

How much does it cost to take an exam?
Each basic exam is $25. The advanced exam is $50. Exam fees are non-refundable.

Can I pay for the exams with a credit card?
We can only accept payment by check or money order at this time.

When will I be notified of my exam results?
Exam results letters are sent within 30 days after the exam day. A list of missed objectives is printed on the exam results letter, which help an operator determine which areas of the study guide to focus on.

Continuing Education

What classes can I take to get continuing education credits?
Check our training calendar for a current list of training opportunities, as well as a list of online training providers.

When should I submit my continuing education documentation?
Courtesy renewal reminder letters are mailed six weeks prior to your expiration date, provided that we have a current address for you on file. At that time, mail in your reminder letter, credit documentation, and the appropriate fee before the expiration date on your certificate.

What if I earn more credits than I need?
That's great!! Those credits become a part of your record. However, credits cannot be carried over to the next renewal period. They must be earned within your license period printed on your certificate.

What if I don't have enough credits to renew?
Send in the required continuing education documentation when you have accumulated enough credits and a $70 fee ($45 renewal fee and $25 late fee) to the department to get your certification renewed. You have one year after the expiration of your certificate to renew. If you do not renew your certification within that one year period, you will need to retake exams and be assigned a new operator certification number.

I took a class a few days prior to my certification expiration date and it is not showing up yet on my training history report. What do I need to do to renew my certification on time?

Print your Training History Report and hand-write in the missing class. Mail in your renewal. Once the DNR Operator Certification Program receives the attendance roster from the training provider, we will verify your attendance.

Advanced Certification

What courses are considered "Advanced" and can be used towards advanced certification points?
The DNR will publish a list of courses approved for advanced certification points on September 1st of every year. The first list will be published on September 1, 2015. Advanced coursework is defined as education that is beyond the basic knowledge of a particular aspect of wastewater treatment and is concentrated into only a few subjects. Approved courses will be a least 20 hours in length.

What is considered "wastewater related" courses in regards to the 240 hour requirement to use a bachelor's degree for advanced points?
The following is a list of courses considered to be "wastewater related" topics. This list is not all inclusive: Aquatic Toxicology, General Chemistry, Water Chemistry, Fluid Mechanics, Hydraulics, Hydrology, Microbiology, Soil Science, Water Resources, and Water Quality Modeling

How many classes is 240 hours?
240 contact hours is equivalent to 15-16 college semester credits.

Collection System Certification
Do I need to take the new collection system exam?
If the treatment plant owns the sanitary sewer collection systems associated with it, then at least one person will need to be certified in the collection system subclass. For satellite sewerage collection systems, this certification will be voluntary. However, the Department highly recommends that satellite systems have a certified operator in collection systems.
To become certified, the person will need to take the 50 question multiple choice collection systems exam. No operator certification will be converted into the collections system subclass, since it is a completely new certification type.

Do I need to pass the basic general wastewater exam too, in order to become certified in collection systems?
The basic general wastewater exam is not required for collection system certification.

By when does the collection system certification need to be obtained?
The collection system study guide and exam has not yet been developed and will tentatively be complete in 2017. Once the collection system study guide and exam have been developed by the department, and at the time of WPDES permit reissuance, collection system operators will have a permit term of 5 years to obtain collection system certification.

If the treatment plant is classified as advanced, does the collection system operator need advanced certification?
No, basic level certification is the only level required for all collection systems.

New Subclasses: Nutrient Removal- Total Nitrogen and Anaerobic Treatment of Liquid Waste
I operate a treatment plant that has total nitrogen limits and operates to remove total nitrogen. Will I need to take the new Nutrient Removal - Total Nitrogen exam?
The designated operator-in-charge will need to pass the new Nutrient Removal - Total Nitrogen exam. This exam will be 25 questions, multiple choice. There is a grace period of 12 months to obtain this new certification once the subclass is added to a facility's classification.

I operate a treatment plant that has an anaerobic treatment of liquid waste. Will I need to take the new Anaerobic Treatment of Liquid Waste exam?
The designated operator-in-charge will need to pass the new Anaerobic Treatment of Liquid Waste exam. This exam will be 25 questions, multiple choice. There is a grace period of 12 months to obtain this new certification once the subclass is added to a facility's classification.

Back to Top


The Certified Operator

"The Certified Operator" is the annual newsletter of the Operator Certification Program distributed in August to all certified Wastewater and Municipal Waterworks operators. The newsletter highlights program information and updates. DNR has recently begun emailing the newsletter to all operators who have an email address on file. If you are currently receiving the newsletter via regular mail and would like to receive future copies via email, please email your request to (please include your name and certification number in the email).

Current edition of "The Certified Operator"

August 2015 [PDF]

Previous editions of "The Certified Operator"

August 2014 [PDF]

August 2013 [PDF]

August 2012 [PDF]


Contact your regional coordinator for any questions regarding your certification. Experience forms should be mailed to your regional coordinator. If no regional coordinator is listed, send the experience form to the statewide coordinator (address below).

For general questions, you may also contact

Regional coordinators
Regional office Coordinator name Counties of responsibility
South Central Region Contact Statewide Coordinator Columbia, Dane, Dodge, Grant, Green, Iowa, Jefferson, Lafayette, Richland, Rock, Sauk
South Eastern Region Contact Statewide Coordinator Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Walworth, Washington, Waukesha
DNR - Northeast Region
2984 Shawano Ave
Green Bay WI 54313-6727
Dick Sachs
Brown, Calumet, Door, Fond du Lac, Green Lake, Kewaunee, Manitowoc, Marinette, Marquette, Menomonie, Oconto, Outagamie, Shawano, Waupaca, Waushara, Winnebago
West Central Region
Contact Statewide Coordinator Adams, Buffalo, Chippewa, Clark, Crawford, Dunn, Eau Claire, Jackson, Juneau, LaCrosse, Marathon, Monroe, Pepin, Pierce, Portage, St. Croix, Trempealeau, Vernon, Wood
Northern Region Contact Statewide Coordinator Ashland, Barron, Bayfield, Burnett, Douglas, Florence, Forest, Iron, Langlade, Lincoln, Oneida, Polk, Price, Rusk, Sawyer, Taylor, Vilas, Washburn

Statewide Coordinator

Lisa Bushby
DNR Statewide Operator Certification Coordinator
PO Box 7921, Madison WI 53707-7921
Phone 608-266-0498
Fax 608-266-5226

Section Chief, Operator Certification Program

Steve Geis

Last revised: Friday October 30 2015