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Question 1

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Under Ohio Revised Code Chapter 6109, which agency certifies water and wastewater system operators?

Ohio Department of Health

Ohio Environmental Protection Agency (Ohio EPA)

Ohio Department of Natural Resources

Ohio Department of Agriculture

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Sample OH Water/Wastewater Operator Practice Questions

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1Under Ohio Revised Code Chapter 6109, which agency certifies water and wastewater system operators?

A.Ohio Department of Health

B.Ohio Environmental Protection Agency (Ohio EPA)

C.Ohio Department of Natural Resources

D.Ohio Department of Agriculture

Explanation: The Ohio Environmental Protection Agency (Ohio EPA) administers the operator certification program under ORC Chapter 6109 for water supply and Chapter 6111 for water reclamation (wastewater). Ohio EPA sets certification classes, administers exams through approved providers, and enforces operator qualification standards statewide.

2What are the certification classes for Ohio water supply operators under OAC 3745-7?

A.Levels 1-5

B.Grades A, B, C, D

C.Class I, Class II, Class III, and Class A

D.Operator-in-Training and Full Operator only

Explanation: Ohio EPA certifies water supply operators at Class I, Class II, Class III, and Class A levels under OAC 3745-7-05. Class I is the entry level for small systems, while Class A is the highest certification for the most complex treatment facilities. Operators at each level must demonstrate progressively greater knowledge and experience.

3What minimum exam score is required to pass the Ohio water operator certification exam?

A.60%

B.65%

C.70%

D.75%

Explanation: Ohio EPA requires a minimum score of 70% on the certification examination. Once an operator achieves a score of 70 or above and can document the appropriate level of hands-on experience, the operator can apply for full certification at their designated class level.

4What is the minimum operating experience required for initial Ohio water operator certification?

A.520 hours OR 2 years work experience

B.1,040 hours OR 3 years work experience

C.2,080 hours OR 5 years work experience

D.No experience required

Explanation: To receive an Ohio water operator certificate, you must document 1,040 hours of operating experience OR 3 years of working experience in the field. However, completion of approved correspondence courses (such as OTCO Basic Water or Cal State Sacramento courses) can reduce the experience requirement to 1 year or 520 hours.

5Which organization provides Ohio EPA's water operator certification examinations?

A.Pearson VUE

B.PSI Services

C.Water Professionals International (WPI)

D.Prometric

Explanation: Ohio EPA offers professional water and wastewater operator certification examinations through Water Professionals International (WPI), formerly known as ABC (Association of Boards of Certification). Candidates schedule exams through the PSI online portal at test-takers.psiexams.com/abc-oh.

6What is the Operator-in-Training (OIT) designation in Ohio's water operator program?

A.A temporary license for operators who failed the exam

B.A status for operators who passed the exam but lack the required experience

C.An apprenticeship program run by community colleges

D.A mandatory internship before taking the exam

Explanation: An Operator-in-Training (OIT) is someone who has passed the Ohio EPA certification exam but has not yet accumulated the required operating experience for full certification. OIT status allows operators to gain hands-on experience while working under the supervision of a certified operator at the appropriate class level.

7What is the non-refundable application fee for Ohio water operator certification?

A.$25

B.$35

C.$45

D.$75

Explanation: All operators who submit a third-party application for Ohio EPA water or wastewater certification must pay a $45 non-refundable application fee. This is separate from any testing center fees charged by WPI/PSI for the examination itself.

8The primary purpose of chlorination in water treatment is to:

A.Improve water taste and odor

B.Remove turbidity from raw water

C.Destroy pathogenic microorganisms

D.Lower water hardness

Explanation: The primary purpose of chlorination is disinfection — destroying pathogenic (disease-causing) microorganisms such as bacteria, viruses, and protozoa. While chlorine can also help with taste, odor, and color control as secondary benefits, its essential function in water treatment is providing a disinfection barrier to prevent waterborne illness.

9What is the maximum contaminant level (MCL) for total trihalomethanes (TTHMs) in drinking water under EPA and Ohio EPA regulations?

A.0.010 mg/L

B.0.040 mg/L

C.0.080 mg/L

D.0.100 mg/L

Explanation: The EPA MCL for total trihalomethanes (TTHMs) is 0.080 mg/L (80 ppb), which Ohio EPA enforces. TTHMs are disinfection byproducts formed when chlorine reacts with natural organic matter in source water. Systems must monitor and report TTHM levels as a running annual average to ensure compliance.

10During the coagulation process, which chemical is MOST commonly used as a primary coagulant in Ohio water treatment plants?

A.Sodium hydroxide

B.Aluminum sulfate (alum)

C.Potassium permanganate

D.Activated carbon

Explanation: Aluminum sulfate (alum) is the most widely used primary coagulant in conventional water treatment. Alum works by neutralizing the negative charges on colloidal particles, allowing them to aggregate into larger particles (floc) that can be removed by sedimentation and filtration. Ferric chloride and polyaluminum chloride are also common alternatives.

About the OH Water/Wastewater Operator Exam

The Ohio water and wastewater operator certification exam covers OAC 3745-7, ORC Chapters 6109 and 6111, water treatment processes, wastewater treatment including activated sludge, distribution and collection systems, pump operations, laboratory testing, safety procedures, and math calculations.

Questions

100 scored questions

Time Limit

2-3 hours

Passing Score

70%

Exam Fee

$45 application fee + testing center fees (Ohio Environmental Protection Agency (Ohio EPA))

OH Water/Wastewater Operator Exam Content Outline

20%

State Laws & Regulations

OAC 3745-7, ORC 6109/6111, certification classes, NPDES permits, and public notification

20%

Water Treatment

Coagulation, flocculation, sedimentation, filtration, disinfection, and CT calculations

20%

Wastewater Treatment

Activated sludge, sludge handling, BOD/TSS removal, and process control

20%

Distribution & Collection

Pumps, hydraulics, cross-connection control, and collection system operations

20%

Laboratory & Safety

Water quality testing, sampling procedures, record-keeping, and safety protocols

How to Pass the OH Water/Wastewater Operator Exam

What You Need to Know

Passing score: 70%
Exam length: 100 questions
Time limit: 2-3 hours
Exam fee: $45 application fee + testing center fees

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

Frequently Asked Questions

What certification classes does Ohio offer for water operators?

Ohio offers Class I, II, III, and Class A water supply certifications, plus corresponding wastewater (water reclamation) certifications. Operators can also hold OIT (Operator-in-Training) status after passing the exam but before completing experience requirements.

How do I schedule the Ohio water operator exam?

Ohio EPA exams are administered through Water Professionals International (WPI) via the PSI online portal at test-takers.psiexams.com/abc-oh. The application fee is $45 non-refundable.

Can training reduce the Ohio experience requirement?

Yes — completing OTCO or Cal State Sacramento approved correspondence courses reduces the experience requirement from 1,040 hours (or 3 years) to 520 hours (or 1 year).