Median Pay by Area
- Bozeman
- $76,390 a year
- Missoula
- $66,550 a year
- Billings
- $60,530 a year
- Helena
- $57,410 a year
- Great Falls
- $56,900 a year
- West Montana (non-metro)
- $52,800 a year
Montana wastewater operators
The steps from no certificate to a Montana Class 3C or 1C wastewater operator certificate, how to register for and take the exam, how to keep your certificate active and what operators earn. Every requirement links to the Montana Department of Environmental Quality (DEQ) Water and Wastewater Operator Certification Program or to Montana law, MCA Title 37, Chapter 42.
DEQ makes the final eligibility determination. Check with DEQ before you apply.
Why it matters
Montana law makes it unlawful to run a wastewater treatment plant, or to do the duties of an operator, without a DEQ certificate. Public and private plants must be supervised by an operator certified at a grade matching the plant's classification.
DEQ says all community and non-transient non-community drinking water systems and wastewater systems must be operated under the supervision of a fully certified operator.
Facilities that discharge to a municipal plant do not need their own certified operator unless the municipality requires one.
If a system has no certified operator, DEQ asks the owner to email the Operator Certification Program. The owner can also ask DEQ for a temporary certificate for an operator who does not yet meet the full requirements.
Municipal wastewater operators hold a Class C Wastewater System Operator certificate. DEQ uses two classes: Class 1C for mechanical plants and Class 3C for lagoons.
Class 1C covers secondary and advanced treatment such as conventional and extended aeration activated sludge, oxidation ditches, package plants, biological nutrient removal, trickling filters, bio-discs, sequencing batch reactors, effluent filtration and membrane bioreactors.
Class 3C covers secondary treatment by aerated lagoons or lagoons without artificial aeration.
DEQ also certifies Industrial Wastewater Treatment Operators (Classes 1D to 4D) and On-site Wastewater System Operators (Classes 2E to 4E). The certificate categories DEQ lists do not include a separate collection system certificate.
Step 1
The first step is to fill out and submit the wastewater operator application. When DEQ receives it, the office sends you a small welcome packet.
Include a copy of your high school or college diploma or transcripts, or your GED certificate. If you have none of these, you take DEQ's competency assessment.
List your wastewater work history in detail on the application. The experience you report decides whether you become an operator in training or a fully certified operator.
The wastewater application fee is $70 and is good for one year. Fees are non-refundable.
New applicants must send the application, fees and education proof at least 30 days before the exam date. DEQ says there are no exceptions.
Step 2
Full certification needs 1.5 years of experience for Class 3C and 2.5 years for Class 1C.
Two days of post-secondary engineering education, or the equivalent, can replace one day of experience, up to half of the experience requirement. List the dates and degrees and send transcripts, or the education will not be considered.
Step 3
DEQ's Study Materials and Exam Prep section links the Need-to-Know Criteria for Class 1C and Class 3C, the Wastewater Formula/Conversion Table and ABC sample exam questions.
DEQ lists approved references for ABC's standardized wastewater treatment exams, including Sacramento State's Operation of Wastewater Treatment Plants, Volumes I and II, and asks you to use the latest editions.
DEQ also posts a Basic Lagoon Wastewater Treatment Manual, wastewater standard operating procedures and recorded review sessions, including Math for Water Operators.
Step 4
Exams are offered at the MRWS Conference, Spring Water School and Fall Water School, and by appointment at the DEQ office in Helena. DEQ lists upcoming exam dates in its Upcoming Training and Exams panel.
To register, contact the Operator Certification Program and send the exam registration form with the $70 fee for each exam. If you already have an application on file, the form is due 15 days before the exam; new applicants need 30 days.
Exam review sessions at Water Schools and the MRWS Conference are separate. Register for the review with the training provider too; they may charge their own fee.
Step 5
Allow 4 to 6 weeks to receive exam results in the mail.
DEQ issues certificates that name the classification of plant you are qualified to supervise. Montana law says the certificate must be displayed prominently in the operator's office.
Step 6
Certificates are renewed every year by June 30. DEQ mails renewal notices in late April or early May. The wastewater renewal fee is $40, which covers one or more of your C, D and E certificates, and a $30 late fee applies after June 30.
Under Montana law, a certificate not renewed before July 1 is suspended, and DEQ revokes one that stays suspended more than 30 days after giving notice.
Continuing education credits (CECs) are due every even-numbered year by May 31. The current period runs June 1, 2026, to May 31, 2028, and extra credits do not carry over.
A fully certified Class 1 operator needs 2.0 CECs (20 hours) each period and a Class 2 to 4 operator needs 1.0 CEC (10 hours). Operators in training need half as much. One CEC is 10 contact hours.
Courses must be approved by DEQ before they earn CECs. Training not directly tied to plant operation may earn only half credit. You can check your CEC total online with your operator ID number.
If you leave your job, you may keep your certificate for 2 years as long as you meet the other requirements. After that it is automatically invalidated.
Exam day
DEQ gives the exams itself at scheduled sessions and its office. DEQ lists the ABC equivalent of Class 1C as Class II Wastewater Treatment, and of Class 3C as Small Wastewater System Operator.
Bring a photo ID, a basic calculator and No. 2 pencils.
For formulas, DEQ links the WPI Wastewater Formula/Conversion Table for Wastewater Treatment, Collection, Industrial Waste and Wastewater Laboratory exams.
DEQ's pages do not state the passing score, number of questions or time limit. Ask the Operator Certification Program when you register.
Operator Master has free practice questions with an explanation after every answer, a timed full-length practice exam and step-by-step math help built on the WPI formula table. It is an independent study tool, not the official exam.
Pay
The median pay for water and wastewater treatment plant and system operators in Montana was $58,040 a year ($27.90 an hour) in 2025, compared with $60,020 nationally. One in ten earned $37,320 or less, and one in ten earned $81,420 or more.
These federal figures cover drinking water and wastewater operators together, at every level. Pay for a new operator is usually nearer the low end.
Moving up
These are Montana's municipal wastewater classes. Each also needs a high school diploma, GED or DEQ competency assessment and a passing exam. Post-secondary engineering education can replace up to half of the experience.
From another state
To be certified by reciprocity, you must hold a valid water or wastewater certificate from another state, meet Montana's minimum experience for the certificate you want and be in responsible charge of a system in Montana. DEQ's FAQ says you must be employed by a Montana system to apply.
Complete a Montana application for the class comparable to your current certificate. Send a letter explaining the other state's requirements, how you met them and your experience, plus copies of your certificates and the other state's certification contact.
The fees are a $70 reciprocity fee and a $70 application fee. Because DEQ checks with other states, approval can take up to six weeks, and the certificate comes by mail.