Ohio Wastewater Operator Certification (Water Reclamation)
Ohio certifies wastewater treatment operators through Ohio EPA's Operator Certification program, under Ohio Administrative Code Chapter 3745-7. One thing to know up front: Ohio calls the wastewater treatment certificate Water Reclamation. Same job, different name. Here's how to get it.
Requirements and fees change. Always confirm the current details with Ohio EPA Operator Certification (opcert@epa.ohio.gov, 1-866-411-6728) before you apply. This guide is an overview, not the rulebook.
Key takeaways
- Water Reclamation runs Class A (entry), then Class I to IV (IV is highest). Collection is a separate certificate with only Class I and II.
- Every class needs a high-school diploma or equivalent. The only required course is a review of Ohio EPA's own certification training.
- Classes A to III are tested through WPI, scheduled with PSI, with 70 to pass. Class IV is a different process.
- Certificates renew every 2 years.
- Practice with the free Ohio tests, starting with Wastewater Class 1.
Step 1: Know which class your plant needs
Plants are classed by design flow and permit limits. For plants with strict limits (CBOD 10 mg/L or lower, TSS 12 or lower, or ammonia 1 or lower), the breakpoints are 0.025 MGD (Class A), 0.15 (Class I), 1.0 (Class II) and 5.0 (Class III), with Class IV at 5 MGD or more. Other plants use breakpoints of 0.25, 2.0 and 7.5 MGD. Lagoons over 0.025 MGD are Class I.
The operator of record must hold a certificate at or above the plant's class, and must be on site a minimum amount of time: from 2 days and 1 hour a week at a Class A plant, up to 5 days and 40 hours at Class III and IV plants.
Step 2: Meet the requirements
| Class | Experience (with a high-school diploma) |
|---|---|
| A | 1,040 operating hours or 3 years of work experience |
| I | 1 year |
| II | 2 years |
| III | 4 years |
| IV | 2 years of management experience at a Class III or IV plant while holding a Class III |
Ways to shorten it: - Class A: an associate degree cuts it to 780 hours or 2 years, and a bachelor's to 520 hours or 1 year. So does completing a Basic Wastewater course (OTCO) or Sacramento State's Small Wastewater System O&M Vol. I. - Classes II and III: a qualifying bachelor's degree (engineering or a physical or natural science), or a two-year water/wastewater technical degree, cuts Class II by a year and Class III by three. - College without a degree: each year can count as a year of experience. - The other certificate: holding an equal or higher water certificate cuts the experience in half. You always need at least one year in the field.
Some experience counts only partly. Lab, SCADA, sludge and collection work count for up to 25% of a treatment requirement, and septage hauling and clerical work don't count at all.
Step 3: Take the exam
For Classes A to III, you register for the WPI exam through PSI (choose Water/Wastewater, then Ohio EPA, then your level). You need a score of 70 or above. After you pass, you apply for the certificate through the Ohio EPA eBusiness Center. The certificate fee is $45. If you fail, you have to wait at least 30 days to retest.
Class IV isn't a WPI test. Candidates submit an exam within 2 years of being approved, and Ohio EPA's Advisory Council reviews it and recommends a pass or a return. Some people need more than one try.
The free wastewater math practice test and math formulas guide cover the calculations.
Step 4: Use the Operator-in-Training route if you need it
For Classes A, I, II and III, you can pass the exam first and then finish your experience as an Operator-in-Training, with up to 5 years to complete it. An OIT isn't certified yet and can't be the operator of record. There's no OIT route for Class IV.
Step 5: Renew every 2 years
Certificates expire December 31 of the second year after they're issued, and the renewal application is due by November 30 of the expiration year. Contact hours per cycle:
- Class A: 8
- Class I: 12
- Classes II to IV: 24
If you hold more than one certificate, each drops by 25%. At least half of your hours must be operation and maintenance topics. Renewal costs $25 to $65 depending on class, with higher fees if you're more than 30 days late. More than 6 months past expiration, you have to test again.
Two quirks: earning Class II Water Reclamation cancels your lower Water Reclamation and collection certificates, and a Class I Water Reclamation certificate also covers a Class I sewer system.
Moving to Ohio with a license
Ohio considers reciprocity if you hold a current certificate from another state earned by written exam or WPI, and you send a copy of that exam. You must also meet Ohio's experience rules. The Advisory Council compares exams and experience and may grant a lower class than you hold now, especially if your state doesn't share its exams.
Next steps
- Check current rules with Ohio EPA Operator Certification.
- Practice: Class A and I, Class II, Class III, Class IV, or the Ohio wastewater flashcards. The 30-day wastewater study plan lays out a schedule.
- Working on the water side too? See how to become a water operator in Ohio.
Sources: OAC 3745-7 (rules effective July 3, 2025); ORC 3745.11; Ohio EPA "How to Become an Operator" fact sheet (June 2025); Advisory Council minutes (March 2026). Reviewed October 2026.