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Small water system (OTM/NN) operator certification

Small water system operators work at an "other than municipal" (OTM) community water system or a non–transient non–community (NN) water system. OTM systems serve groups of 25 or more year-round residents; they can include mobile home parks, apartments, condominiums and other facilities. NN systems serve groups of 25 or more people over six months of the year; examples include schools, day care centers, dairies and cheese plants, factories and industrial facilities. All OTM and NN public water systems are required to have a certified operator.

A "certified operator" is an individual who has met the requirements of Chapter NR 114, Wisconsin Administrative Code, and has been issued a certificate by the DNR to work at a water system.

Becoming a certified operator entails meeting the education requirement and passing the water system general operation exam. The education requirement is a high school diploma or general equivalency degree. (Operators who have at least two years of experience operating a water system, obtained before December 1, 2000, can substitute experience for this education requirement.)

The water system general operation exam is offered twice a year (May and November) in six locations around the state. Submit an application by the deadline if you want to take the exam, and the exam fee is $25. A score of at least 75% is required to pass the exam and become a certified operator. Click on the link for exam dates (on the right) for more information about applying to take the exam. Click on the "Exam study options" tab (above) for help preparing to take the exam.

Operators who already hold current municipal waterworks certifications in the distribution system, groundwater source, or surface water source subclasses (D, G or S) are also qualified to operate small (OTM/NN) water systems, and do not need to take the general operation exam.

The operator certification lasts for three years and can be renewed. Click on the Renew tab above for information about how to renew your certification. The fee for renewing is $45.

Certified operators need continuing education to qualify for renewal. Once certified, you must earn six hours of continuing education credits during every three-year license period to renew your certification. Click on the "Continuing ed" tab above for more information about the available training options.


All OTM and NN water systems are required to have a qualified certified operator managing their system. The rule also requires owners of small public water systems to designate an "operator–in–charge" of their system and to keep the DNR informed about any personnel changes.

A water system can find itself out of compliance with the drinking water requirements if it does not have a certified operator or operator-in-charge (either on staff or retained on a contract basis), if it loses its operator (due to staff changes, for instance), or if its operator's certification expires and has not been renewed. For this reason, some systems have more than one certified operator as a safeguard. Systems in need can also get help from certified operators who offer their services on a contract basis (see the contract operators tab above for more information).

The DNR tracks compliance with these requirements, and a graduated enforcement process is triggered whenever a public water system lacks at least one certified operator. DNR's tracking system automatically notes any "preliminary violations", and DNR's field staff follow up to verify the system's status and offer information and compliance assistance where needed. DNR issues a Notice of Non–compliance (NON) to inform the system owner about a violation and specify a time period for correcting it. The system owner can come back into compliance by fulfilling the requirements for a certified operator and/or operator–in–charge. DNR issues a Notice of Violation (NOV) if a system is not brought back into compliance.

Contact us (see the contacts tab above) if you have questions or need more information about the requirements.

Both self–study and classroom study options are available for people wanting to prepare for the small system operator exam.

Passing the general exam provides the operator with a basic level of certification. To build on this basic knowledge, to acquire new skills and to stay current with regulatory requirements, operators must complete six hours of continuing education credits during a 3–year certification period. The Wisconsin DNR contracts with a third-party contractor to provide continuing education for OTM/NN operators classes free of charge. Visit operator training for more information on the courses offered, the locations and schedule of available classes. OTM/NN operators should take courses indicated by the "OTM/NN" designation.

Credits must be earned within the 3-year certification period. For example: If November 1, 2016, is the expiration date of the certification, continuing education credits must be earned between November 1, 2013, and November 1, 2016, to be valid for renewal.

DNR sends training reminder letters to operators approximately 6 months before their certification expiration date. Then, about 6 weeks before their certification expiration date, operators are sent a renewal reminder letter. It is important for operators to keep their address current by notifying the statewide coordinator of any changes.

The renewal reminder 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 renewal reminder letter, their continuing education documentation, and the $45 renewal fee to:

Operator Certification Program — EAS/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 retake the exams as a new operator.


Public water systems can be located at many small businesses that may not have a large staff or their own fulltime operator. Some certified operators provide services to public water systems on a contract basis.

DNR maintains a list of available contract operators in Wisconsin, and certified operators who provide contract services can be listed upon request. DNR provides this list as a source of information for small water systems, and it does not represent an endorsement or recommendation.

  • List of certified operators in Wisconsin providing contract services.
  • If you are a certified operator who offers contract services and want to be included on this list, contact the Operator Certification Program at 608-266-0498 or
How do I get an application to take an exam?
Exam applications are available on the exams web page ten weeks prior to the exam date.
How much does it cost to take an exam?
The exam is $25. Exam fees are non-refundable.
When will I be notified of my exam results?
Exam results letters are sent normally within 30 days of the exam day.
What classes can I take to get continuing education credits?
Continuing education credit courses must be pre-approved by the department for certified water system operators. The DNR offers both free and pre-approved continuing education courses through a contract with Moraine Park Technical College. Please visit the operator training calendar for a list of events approved for continuing education by the Wisconsin DNR Operator Certification program. An additional option for already certified water system operators is to take the free OTM/NN Water System Operator Exam Review class listed on the operator training calendar for 4 continuing education credits. This class is offered six times annually by the Wisconsin Rural Water Association. There may also be a limited selection of pay–to– register in-person courses listed on the training calendar as well, that are not funded by DNR. Water system operators will need to take courses indicated by the "OTM/NN" designation.
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, your continuing education documentation, and the appropriate fee before the expiration date on your certificate.
What if I earn more credits than I need?
That's great!! Send along any extra credits you have and they become a part of your record. Credits cannot be carried over to the next renewal period.
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 penalty 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, your operator record will be deleted, and you will have to retake the exam. If you are the only certified operator for a system, the day your certification expires, your system will be in violation and a notice of non-compliance will be sent out.

Contact your regional coordinator for any questions regarding your certification.

Printer-friendly list of waterworks coordinators

Regional Coordinators

Regional office Coordinator name Counties of responsibility
DNR — South Central Region
3911 Fish Hatchery Rd
Fitchburg WI 53711
Sarah Graves Graber
Columbia, Crawford, Dane, Dodge, Grant, Green, Iowa, Jefferson, Lafayette, Richland, Rock, Sauk
DNR — Southeast Region
1155 Pilgrim Rd
Plymouth WI 53073
Stephanie Pfeiffer
Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Walworth, Washington, Waukesha
DNR — Northeast Region
2984 Shawano Ave
Green Bay WI 54313–6727
Heather Hermes
Brown, Calumet, Door, Fond du Lac, Green Lake, Kewaunee, Manitowoc, Marinette, Marquette, Menomonie, Oconto, Outagamie, Shawano, Waupaca, Waushara, Winnebago
DNR — West Central Region
1300 W Clairemont Ave
Eau Claire WI 54701
Pat Radle
Adams, Buffalo, Chippewa, Clark, Dunn, Eau Claire, Jackson, Juneau, La Crosse, Marathon, Monroe, Pepin, Pierce, Portage, St. Croix, Trempealeau, Vernon, Wood
DNR — Northern Region
810 Maple St
Spooner WI 54801
Sarah Graves Graber
Ashland, Barron, Bayfield, Burnett, Douglas, Florence, Forest, Iron, Langlade, Lincoln, Oneida, Polk, Price, Rusk, Sawyer, Taylor, Vilas, Washburn

Statewide Coordinator

PO Box 7921 - EA/7
Madison WI 53707–7921

Program Assistant

Jordan Schutz
Phone: 608–228-5190

For general questions, contact