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IOWA WATER TREATMENT OPERATOR GRADE II
EXAM QUESTIONS AND CORRECT ANSWERS WITH
RATIONALES
IOWA WATER TREATMENT OPERATOR GRADE II EXAM
10 MOST RELEVANT AND TESTED COVERAGE AREAS
1. Iowa DNR Operator Certification Requirements and Chapter 81
2. Water Treatment Plant Classification, Grade II Responsibilities, and Operator Requirements
3. Coagulation, Flocculation, Sedimentation, and Clarification
4. Filtration, Filter Operation, Backwashing, and Filter Troubleshooting
5. Disinfection, Chlorination, CT Concepts, and Chlorine Safety
6. Water Chemistry, pH, Alkalinity, Hardness, Turbidity, and Chemical Dosage
7. Iron and Manganese Removal, Aeration, and Chemical Treatment
8. Fluoridation, Corrosion Control, Softening, and Other Treatment Processes
9. Pumps, Motors, Instrumentation, Flow Measurement, Maintenance, and Process Control
10. Sampling, Laboratory Analysis, Drinking-Water Regulations, Safety, Records, and Emergency
Response
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QUESTIONS 1–200
1. Which Iowa agency is responsible for certifying public water supply treatment operators under
Chapter 81?
A. Iowa Department of Natural Resources
B. Iowa Department of Public Health
C. Iowa Utilities Board
D. Iowa Department of Agriculture
Answer: A
Rationale: The Iowa Department of Natural Resources administers the Drinking Water and Wastewater
Operator Certification program under Chapter 81. The program establishes certification requirements
and examinations for public water supply treatment and distribution operators. (Department of Natural
Resources)
2. What minimum operating experience is generally required for an Iowa Grade II water treatment
certificate?
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A. One year
B. Two years
C. Three years
D. Four years
Answer: C
Rationale: Iowa's current certification table lists three years of operating experience for Grade II
certification, with certain allowable substitutions under Chapter 81.6. A high school diploma or GED is
also specified. (Iowa Legislature)
3. Which treatment process is specifically associated with removal of settleable material before
filtration?
A. Fluoridation
B. Sedimentation
C. Disinfection
D. Stabilization
Answer: B
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Rationale: Sedimentation allows suspended particles and flocculated material to settle under relatively
quiescent conditions. Removing this material before filtration reduces filter loading and improves
downstream treatment performance.
4. Why is coagulation used during conventional drinking-water treatment?
A. To increase fluoride concentration
B. To disinfect finished water
C. To raise finished-water temperature
D. To destabilize suspended and colloidal particles
Answer: D
Rationale: Coagulation destabilizes particles that otherwise remain suspended because of electrical and
physical forces. Once destabilized, particles can collide and form larger flocs during flocculation.
5. Which chemical characteristic most directly affects the performance of many coagulation
processes?
IOWA WATER TREATMENT OPERATOR GRADE II
EXAM QUESTIONS AND CORRECT ANSWERS WITH
RATIONALES
IOWA WATER TREATMENT OPERATOR GRADE II EXAM
10 MOST RELEVANT AND TESTED COVERAGE AREAS
1. Iowa DNR Operator Certification Requirements and Chapter 81
2. Water Treatment Plant Classification, Grade II Responsibilities, and Operator Requirements
3. Coagulation, Flocculation, Sedimentation, and Clarification
4. Filtration, Filter Operation, Backwashing, and Filter Troubleshooting
5. Disinfection, Chlorination, CT Concepts, and Chlorine Safety
6. Water Chemistry, pH, Alkalinity, Hardness, Turbidity, and Chemical Dosage
7. Iron and Manganese Removal, Aeration, and Chemical Treatment
8. Fluoridation, Corrosion Control, Softening, and Other Treatment Processes
9. Pumps, Motors, Instrumentation, Flow Measurement, Maintenance, and Process Control
10. Sampling, Laboratory Analysis, Drinking-Water Regulations, Safety, Records, and Emergency
Response
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QUESTIONS 1–200
1. Which Iowa agency is responsible for certifying public water supply treatment operators under
Chapter 81?
A. Iowa Department of Natural Resources
B. Iowa Department of Public Health
C. Iowa Utilities Board
D. Iowa Department of Agriculture
Answer: A
Rationale: The Iowa Department of Natural Resources administers the Drinking Water and Wastewater
Operator Certification program under Chapter 81. The program establishes certification requirements
and examinations for public water supply treatment and distribution operators. (Department of Natural
Resources)
2. What minimum operating experience is generally required for an Iowa Grade II water treatment
certificate?
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A. One year
B. Two years
C. Three years
D. Four years
Answer: C
Rationale: Iowa's current certification table lists three years of operating experience for Grade II
certification, with certain allowable substitutions under Chapter 81.6. A high school diploma or GED is
also specified. (Iowa Legislature)
3. Which treatment process is specifically associated with removal of settleable material before
filtration?
A. Fluoridation
B. Sedimentation
C. Disinfection
D. Stabilization
Answer: B
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Rationale: Sedimentation allows suspended particles and flocculated material to settle under relatively
quiescent conditions. Removing this material before filtration reduces filter loading and improves
downstream treatment performance.
4. Why is coagulation used during conventional drinking-water treatment?
A. To increase fluoride concentration
B. To disinfect finished water
C. To raise finished-water temperature
D. To destabilize suspended and colloidal particles
Answer: D
Rationale: Coagulation destabilizes particles that otherwise remain suspended because of electrical and
physical forces. Once destabilized, particles can collide and form larger flocs during flocculation.
5. Which chemical characteristic most directly affects the performance of many coagulation
processes?
