CALIFORNIA WASTEWATER TREATMENT OPERATOR
GRADE 5 EXAM GUIDE WITH QUESTIONS AND
ANSWERS 2026/27
1. Which subject area is NOT explicitly included in the California Grade V WWTP Operator
Examination content outline?
A. Safety practices and hazards encountered during operations
B. Anaerobic sludge digestion and disinfection
C. Design and construction of wastewater treatment facilities
D. Process control and activated sludge process modifications
Correct Answer: C
Explanation: The Grade V exam covers operation and maintenance, not design/construction. The
official outline includes safety, sampling, unit processes, digestion, disinfection, stabilization
ponds, regulations, sludge handling, process control, activated sludge modifications, tertiary
treatment, water reclamation, and supervision/management responsibilities.
2. What is the passing score requirement for the mathematics section of the Grade V examination?
A. At least 70% of total math points
B. At least 50% of math questions (16 points)
C. At least 60% of total exam points
D. At least 80% of math points with no minimum total
Correct Answer: B
Explanation: examinees must score at least 16 points (50 percent) on the Math Questions AND
achieve a minimum total score of 98 points (70 percent).
3. Which of the following calculations is specifically mentioned as appearing on the Grade V exam?
A. Pipe diameter selection for gravity flow
B. Heat value/gas generation from an anaerobic digester
C. Chemical cost per gallon for buying decisions
D. Structural load calculations for tank walls
Correct Answer: B
Explanation: The Grade V exam includes complex math problems including heat value/gas
generation from anaerobic digesters, BOD/nitrogenous BOD calculations, polymer usage/dose,
disinfection dose/residual/cost, and nitrification effects.
4. How many total points is the Grade V examination worth?
A. 100 points
B. 120 points
C. 140 points
, D. 160 points
Correct Answer: C
Explanation: The examination structure is 25 multiple choice questions (2 points each = 50), 29
multiple choice essay problems (2 points each = 58), and 16 multiple choice math problems (2
points each = 32), totaling 140 points.
5. What is the time limit for completing the Grade V examination?
A. 3 hours
B. 4 hours
C. 5 hours
D. 6 hours
Correct Answer: B
Explanation: Examinees are given 4 hours to complete the examination.
6. Which treatment process modification is specifically tested on the Grade V exam?
A.单纯 filtration systems
B. Activated sludge process modifications
C. Rainwater harvesting systems
D. Solar-powered aeration systems
Correct Answer: B
Explanation: The Grade V examination includes questions on process control, activated sludge
process modifications, and tertiary treatment.
7. What minimum total score is required to pass the Grade V examination?
A. 70 points (50%)
B. 98 points (70%)
C. 105 points (75%)
D. 112 points (80%)
Correct Answer: B
Explanation: To pass, examinees must achieve a minimum total score of 98 points (70 percent)
AND at least 16 points (50%) on math questions.
8. Which of the following is a supervision/management responsibility tested on the Grade V exam?
A. Daily pH testing procedures
B. Energy management and budget development
C. Cleaning sewer pipes
D. Taking grab samples
Correct Answer: B
, Explanation: Supervision/management responsibilities tested include energy management,
safety program development, operator training, and budget development and control.
9. What type of treatment processes are covered regarding wastewater stabilization ponds?
A. Design only
B. Operation and maintenance
C. Construction only
D. Regulatory approval only
Correct Answer: B
Explanation: The exam includes operation and maintenance of wastewater stabilization ponds.
10. Which calculation related to solids processing appears on the Grade V exam?
A. Tank wall thickness requirements
B. Efficiency and loading of solids thickening processes
C. Pump motor horsepower ratings
D. Pipe corrosion rates
Correct Answer: B
Explanation: Exam math includes efficiency and loading of solids thickening processes, polymer
usage/dose, and pumping efficiency/cost.
11. What is the primary focus of primary treatment in wastewater plants?
A. Nutrient removal
B. Removal of settleable solids through sedimentation
C. Dissolved oxygen addition
D. Heavy metal precipitation
Correct Answer: B
Explanation: Primary treatment focuses on removing suspended and settleable solids through
sedimentation.
12. Which gas is commonly produced in anaerobic digesters?
A. Oxygen
B. Carbon monoxide
C. Methane
D. Nitrogen
Correct Answer: C
Explanation: Anaerobic digestion produces methane as a major component of biogas.
13. What does the F/M ratio measure in activated sludge systems?
A. Floc to microorganism ratio
GRADE 5 EXAM GUIDE WITH QUESTIONS AND
ANSWERS 2026/27
1. Which subject area is NOT explicitly included in the California Grade V WWTP Operator
Examination content outline?
A. Safety practices and hazards encountered during operations
B. Anaerobic sludge digestion and disinfection
C. Design and construction of wastewater treatment facilities
D. Process control and activated sludge process modifications
Correct Answer: C
Explanation: The Grade V exam covers operation and maintenance, not design/construction. The
official outline includes safety, sampling, unit processes, digestion, disinfection, stabilization
ponds, regulations, sludge handling, process control, activated sludge modifications, tertiary
treatment, water reclamation, and supervision/management responsibilities.
2. What is the passing score requirement for the mathematics section of the Grade V examination?
A. At least 70% of total math points
B. At least 50% of math questions (16 points)
C. At least 60% of total exam points
D. At least 80% of math points with no minimum total
Correct Answer: B
Explanation: examinees must score at least 16 points (50 percent) on the Math Questions AND
achieve a minimum total score of 98 points (70 percent).
3. Which of the following calculations is specifically mentioned as appearing on the Grade V exam?
A. Pipe diameter selection for gravity flow
B. Heat value/gas generation from an anaerobic digester
C. Chemical cost per gallon for buying decisions
D. Structural load calculations for tank walls
Correct Answer: B
Explanation: The Grade V exam includes complex math problems including heat value/gas
generation from anaerobic digesters, BOD/nitrogenous BOD calculations, polymer usage/dose,
disinfection dose/residual/cost, and nitrification effects.
4. How many total points is the Grade V examination worth?
A. 100 points
B. 120 points
C. 140 points
, D. 160 points
Correct Answer: C
Explanation: The examination structure is 25 multiple choice questions (2 points each = 50), 29
multiple choice essay problems (2 points each = 58), and 16 multiple choice math problems (2
points each = 32), totaling 140 points.
5. What is the time limit for completing the Grade V examination?
A. 3 hours
B. 4 hours
C. 5 hours
D. 6 hours
Correct Answer: B
Explanation: Examinees are given 4 hours to complete the examination.
6. Which treatment process modification is specifically tested on the Grade V exam?
A.单纯 filtration systems
B. Activated sludge process modifications
C. Rainwater harvesting systems
D. Solar-powered aeration systems
Correct Answer: B
Explanation: The Grade V examination includes questions on process control, activated sludge
process modifications, and tertiary treatment.
7. What minimum total score is required to pass the Grade V examination?
A. 70 points (50%)
B. 98 points (70%)
C. 105 points (75%)
D. 112 points (80%)
Correct Answer: B
Explanation: To pass, examinees must achieve a minimum total score of 98 points (70 percent)
AND at least 16 points (50%) on math questions.
8. Which of the following is a supervision/management responsibility tested on the Grade V exam?
A. Daily pH testing procedures
B. Energy management and budget development
C. Cleaning sewer pipes
D. Taking grab samples
Correct Answer: B
, Explanation: Supervision/management responsibilities tested include energy management,
safety program development, operator training, and budget development and control.
9. What type of treatment processes are covered regarding wastewater stabilization ponds?
A. Design only
B. Operation and maintenance
C. Construction only
D. Regulatory approval only
Correct Answer: B
Explanation: The exam includes operation and maintenance of wastewater stabilization ponds.
10. Which calculation related to solids processing appears on the Grade V exam?
A. Tank wall thickness requirements
B. Efficiency and loading of solids thickening processes
C. Pump motor horsepower ratings
D. Pipe corrosion rates
Correct Answer: B
Explanation: Exam math includes efficiency and loading of solids thickening processes, polymer
usage/dose, and pumping efficiency/cost.
11. What is the primary focus of primary treatment in wastewater plants?
A. Nutrient removal
B. Removal of settleable solids through sedimentation
C. Dissolved oxygen addition
D. Heavy metal precipitation
Correct Answer: B
Explanation: Primary treatment focuses on removing suspended and settleable solids through
sedimentation.
12. Which gas is commonly produced in anaerobic digesters?
A. Oxygen
B. Carbon monoxide
C. Methane
D. Nitrogen
Correct Answer: C
Explanation: Anaerobic digestion produces methane as a major component of biogas.
13. What does the F/M ratio measure in activated sludge systems?
A. Floc to microorganism ratio
