Median Pay by Area
- Oklahoma City
- $50,460 a year
- Tulsa
- $49,990 a year
- Lawton
- $40,190 a year
- Northeast Oklahoma (nonmetropolitan)
- $40,530 a year
- Southeast Oklahoma (nonmetropolitan)
- $38,360 a year
Oklahoma wastewater operators
The steps from no certificate to an Oklahoma wastewater works operator certificate, the DEQ-approved training each class needs, how to apply for and pass the state exam, how to renew every year and what operators earn. Every requirement links to the Oklahoma Department of Environmental Quality (DEQ) Operator Certification Unit or its rule, OAC 252:710.
DEQ makes the final eligibility determination. Check with DEQ before you apply.
Why it matters
Oklahoma's rule requires a DEQ certification for everyone who makes decisions about the daily operation of a wastewater system, wastewater treatment facility or collection system, and for anyone who programs or maintains telemetry or SCADA systems or makes process control decisions.
The operator in responsible charge must hold a certification equal to or higher than the class of the system, including each treatment facility and collection system. Assistant superintendents, shift leaders, other supervisors and others who make operating decisions must be certified at the same class as the facility or one class lower.
Nonindustrial wastewater treatment works with an average flow of 5,000 gallons a day or less do not need a certified operator.
If you are hired without a certification and are 18 or older, you must apply for a temporary certification within 10 days of being hired. It lasts one year, cannot be renewed and lets you work under the general supervision of a certified operator. It is not available to superintendents, supervisors or their managers.
A non-certified helper works only under the direct supervision of a certified operator who is present at all times. Time worked as a non-certified helper does not count as experience toward a certification.
DEQ issues Waterworks/Wastewater Works Operator certifications in Class D, C, B and A. It also issues a Class C Distribution and Collection Operator certification, a Class T Distribution and Collection Technician certification and laboratory operator certifications.
Wastewater works are classed by population served and by complexity. Class D covers total retention lagoons and collection systems serving 1,500 people or fewer. Class C covers wastewater works and collection systems serving 1,501 to 15,000 people and discharging facilities serving 15,000 or fewer. Class B covers 15,001 to 50,000 people, and Class A more than 50,000. DEQ can also place a facility in a higher class because of its complexity.
A certified wastewater works operator may do all duties in operating and maintaining wastewater treatment plants, lagoon systems and collection systems. A designated certified operator must be available for each operating shift.
Step 1
You need a high school diploma or GED for a Class A to D certification, although licensed experience or training may be substituted.
Every class needs DEQ-approved training before the exam: 16 hours for Class D, 36 hours for Class C, 100 hours for Class B and 200 hours for Class A. Training counts only if DEQ approved it in advance.
Some substitutions are allowed. One semester hour of college science or engineering can replace 16 classroom hours, and one CEU can replace 10 hours of training. A degree can replace experience or training, but not both.
DEQ's Training Schedule page lists certification classes, open exams and renewal training.
Step 2
Operator applications are on DEQ's Operator Certification Portal. From the portal dashboard you can start a new application, pay invoices, track your applications and see your training hours.
If you already hold an Oklahoma certification, register on the portal as an existing operator with your last name, date of birth and Social Security number. If the portal cannot find you, call DEQ's Operator Certification Section at 405-702-8228.
Step 3
Send your application and the nonrefundable application fee to DEQ at least 21 days before the first day of your standard course (for an exam given at the end of the class) or at least 21 days before the open exam date you want. You must meet all the requirements for the class before you take the exam.
Include evidence of your age, proof of your experience and training (such as transcripts, letters from employers or attendance records) and a signed, notarized affidavit about your legal status. If you hold an equivalent certificate from another state, include proof of it.
If you have not taken the exam within 120 days, you lose the application fee and must apply again.
Fee amounts are set in OAC 252:710-1-12 and are adjusted for inflation each July 1, so check with DEQ for the amount that applies to you.
Step 4
Class D needs no experience. Class C needs one year of waterworks or wastewater works operation. Class B needs three years, including one year of actual hands-on operating experience. Class A needs five years, including two years hands-on.
One year of licensed operational assistance to water or wastewater facilities plus a college degree in a listed science or engineering field can stand in for five years of experience, but it does not count toward the hands-on experience Class A and B require.
You are responsible for keeping your own records of training and experience.
Step 5
You must answer at least 70% of the questions correctly to pass.
DEQ provides a wall certificate when you are first certified and identification credentials when you are certified, change class or renew. DEQ's portal also lets you download your credentials and training records.
If you pass between April 1 and May 31, you do not have to renew the new certification until June of the next calendar year.
Step 6
Certifications are renewed every year. The certificate year runs July 1 to June 30, and your renewal and fees are due by 4:30 p.m. on June 30. Not receiving a renewal invoice does not extend the deadline.
Each year you need DEQ-approved professional development hours (PDHs) based on the highest class you hold: 4 for Class D, 8 for Class C, 12 for Class B and 16 for Class A. At least 4 of those hours must be in-person classroom training.
Online training does not count toward renewal hours for Class D operators or Distribution and Collection Technicians. Training instructors send your attendance record to DEQ, so you do not send proof unless DEQ asks.
You can reactivate an expired certification within two certificate years by completing the training and paying the renewal fees. After more than two years you must apply again and retake the exam.
Exam day
Oklahoma's certification exams are validated exams given by DEQ or its designee. You can take one at the end of a DEQ-approved standard course (a class associated exam) or, if your experience, training and education allow, at an open exam.
DEQ's Wastewater Study Guide says every exam has 100 multiple-choice questions, one point each, covering 12 subject areas. You get an exam booklet, an answer sheet and scratch paper, and most of the math formulas you need are printed in the exam booklet.
The study guide says to bring only a calculator, two No. 2 pencils and your exam approval notice. Its Appendix B shows the formula sheets given with the exam.
You need at least 70% to pass. The study guide says you get a report right after the exam showing your score in each subject area.
If you fail, you must wait at least 30 days before retaking the exam. Anyone found cheating fails and cannot apply for certification for 12 months.
DEQ posts free study guides on its Program Information page, including the Wastewater System Operations Study Guide, the C Level Wastewater Laboratory Manual and the Distribution/Collection Manual.
DEQ gives its own Oklahoma certification exams, with the formulas you need printed in the exam booklet. Operator Master's free practice questions, timed practice exam and math help are built on the WPI exam format and the WPI formula table, so they cover general wastewater knowledge and math, not DEQ's exam questions, format or formula sheets. Use DEQ's Wastewater Study Guide, its formula sheets and your DEQ-approved course as your main guide. Operator Master is an independent study tool, not the official exam.
Pay
The median pay for water and wastewater treatment plant and system operators in Oklahoma was $45,890 a year ($22.06 an hour) in 2025, compared with $60,020 nationally. One in ten earned $35,250 or less, and one in ten earned $63,040 or more.
These federal figures cover drinking water and wastewater operators together, at every class. Pay for a new operator is usually nearer the low end.
Moving up
Every class also needs a passing exam score of at least 70%. Class A to D need a high school diploma or GED, though licensed experience or training may be substituted. Training must be DEQ-approved, and approved equivalents such as college credit or CEUs can replace some training hours.
From another state
DEQ may issue a certification at an equivalent level, without an exam, if you hold a valid certification or license from a state that offers reciprocal certification to Oklahoma operators and has equivalent requirements. You must complete and submit an application.
Active-duty military personnel and their spouses with an equivalent certification can apply before a transfer or discharge to Oklahoma. DEQ issues the certification within 30 days if the other state's certification is valid and reasonably equivalent.
Once you hold an Oklahoma certification by reciprocity, you must meet the same yearly renewal requirements as every other operator.