How to Become a Water Operator in Ohio (Ohio EPA)

Ohio certifies water and wastewater operators through the Ohio EPA Operator Certification Unit. Ohio is a bit different from most states in two ways: it uses five classes (A, I, II, III, IV), and it contracts the exams out to Water Professionals International (WPI), delivered through PSI. Here's how to get certified and move up.

Requirements and fees change. Confirm current details on the Ohio EPA Certified Operators site before applying.

Key takeaways

• Ohio EPA certifies four categories — Water Supply (treatment), Water Distribution, Water Reclamation (wastewater treatment), and Wastewater Collection — each with five classes: A, I, II, III, IV (Class A = small non-community systems; I = entry; IV = highest).
• Pass the WPI exam (110 items, 100 scored, 70% to pass), scheduled through PSI.
• Document the required operating experience (Class A ≈ 1,040 hours; Class I ≈ 12 months; II ≈ 24; III ≈ 48), then apply via the Ohio EPA eBusiness Center ($45 fee).
• Practice with the drinking-water level tests, the distribution hub, and your Ohio state page.

Step 1 — Pick your category

Decide which track you're certifying in: Water Supply (treatment), Water Distribution, Water Reclamation (wastewater treatment), or Wastewater Collection. They're separate certificates, and many operators hold more than one.

Step 2 — Register and take the exam

Ohio EPA does not require any coursework before the exam (though prep helps a lot). Schedule your test through PSI's Ohio EPA portal, choosing Water/Wastewater → Ohio EPA → your level.

The exam has 110 multiple-choice items, 100 of which are scored (the other 10 are unscored pre-test questions), and you need 70% to pass. Because Ohio uses the WPI/ABC framework, the content lines up with the national Need-to-Know criteria.

Ohio EPA doesn't sell study courses or practice exams, so independent practice matters. Use our practice tests — start with a 25-question quick quiz, then build up to the 50-question practice exam and the full-length simulation, reviewing the explanation on every question.

Step 3 — Document your experience

Certification requires operating experience that scales with the class:

• Class A — about 1,040 hours.
• Class I — about 12 months.
• Class II — about 24 months.
• Class III — about 48 months.
• Class IV — the highest, management-level certificate, with the most experience.

Approved training can reduce some experience requirements. Confirm the exact combinations with Ohio EPA.

Step 4 — Apply for the certificate

Once you've passed and can document the experience, apply through the Ohio EPA eBusiness Center. Third-party certification applications carry a $45 non-refundable fee.

Step 5 — Renew and keep learning

Ohio operators renew on a set cycle and must complete continuing education (contact hours) to stay certified. Check your renewal date and required hours in the eBusiness Center, and spread your training across the cycle.

Next steps

1. Confirm your category, class, and current rules on the Ohio EPA Certified Operators site.
2. Read certification levels explained to see how Ohio's A/I–IV classes map to the national ladder.
3. Start practicing from your Ohio state page — and create a free account to save your scores and track weak topics.