AWWA WATER TREATMENT OPERATOR
CERTIFICATION GRADE V EXAM QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS Q&A
2026 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of water treatment?
A. Increase water taste only
B. Remove impurities to make water safe
C. Change water color
D. Add minerals only
Rationale: Water treatment ensures removal of harmful
contaminants to protect public health.
Correct Answer: B
2. Which process removes suspended solids using gravity?
A. Filtration
B. Sedimentation
C. Disinfection
D. Aeration
Rationale: Sedimentation allows heavier particles to settle
naturally.
Correct Answer: B
,3. Chlorine is mainly used for:
A. Coagulation
B. Disinfection
C. Filtration
D. Flocculation
Rationale: Chlorine kills disease-causing microorganisms.
Correct Answer: B
4. Coagulation involves:
A. Settling particles
B. Adding chemicals to destabilize particles
C. Heating water
D. Filtering water
Rationale: Coagulants neutralize particle charges for removal.
Correct Answer: B
5. Flocculation is:
A. Rapid mixing
B. Gentle mixing to form flocs
C. Disinfection process
D. Sediment removal
Rationale: Flocculation aggregates particles into larger flocs.
Correct Answer: B
,6. Filtration removes:
A. Dissolved salts
B. Suspended solids
C. Oxygen
D. Chlorine
Rationale: Filters trap remaining particles after sedimentation.
Correct Answer: B
7. pH measures:
A. Turbidity
B. Acidity or alkalinity
C. Temperature
D. Hardness
Rationale: pH indicates hydrogen ion concentration.
Correct Answer: B
8. Ideal drinking water pH range is:
A. 0–2
B. 3–5
C. 6.5–8.5
D. 9–12
Rationale: Safe drinking water is slightly neutral.
Correct Answer: C
, 9. Turbidity refers to:
A. Water color
B. Cloudiness of water
C. Temperature
D. Taste
Rationale: Turbidity measures suspended particles.
Correct Answer: B
10. Hardness in water is caused by:
A. Sodium and potassium
B. Calcium and magnesium
C. Chlorine
D. Iron only
Rationale: Hardness is due to calcium and magnesium ions.
Correct Answer: B
11. The main disinfectant in most water plants is:
A. Oxygen
B. Chlorine
C. Nitrogen
D. Hydrogen
Rationale: Chlorine is widely used due to effectiveness and
cost.
Correct Answer: B
CERTIFICATION GRADE V EXAM QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS Q&A
2026 |INSTANT DOWNLOAD PDF
1. What is the primary purpose of water treatment?
A. Increase water taste only
B. Remove impurities to make water safe
C. Change water color
D. Add minerals only
Rationale: Water treatment ensures removal of harmful
contaminants to protect public health.
Correct Answer: B
2. Which process removes suspended solids using gravity?
A. Filtration
B. Sedimentation
C. Disinfection
D. Aeration
Rationale: Sedimentation allows heavier particles to settle
naturally.
Correct Answer: B
,3. Chlorine is mainly used for:
A. Coagulation
B. Disinfection
C. Filtration
D. Flocculation
Rationale: Chlorine kills disease-causing microorganisms.
Correct Answer: B
4. Coagulation involves:
A. Settling particles
B. Adding chemicals to destabilize particles
C. Heating water
D. Filtering water
Rationale: Coagulants neutralize particle charges for removal.
Correct Answer: B
5. Flocculation is:
A. Rapid mixing
B. Gentle mixing to form flocs
C. Disinfection process
D. Sediment removal
Rationale: Flocculation aggregates particles into larger flocs.
Correct Answer: B
,6. Filtration removes:
A. Dissolved salts
B. Suspended solids
C. Oxygen
D. Chlorine
Rationale: Filters trap remaining particles after sedimentation.
Correct Answer: B
7. pH measures:
A. Turbidity
B. Acidity or alkalinity
C. Temperature
D. Hardness
Rationale: pH indicates hydrogen ion concentration.
Correct Answer: B
8. Ideal drinking water pH range is:
A. 0–2
B. 3–5
C. 6.5–8.5
D. 9–12
Rationale: Safe drinking water is slightly neutral.
Correct Answer: C
, 9. Turbidity refers to:
A. Water color
B. Cloudiness of water
C. Temperature
D. Taste
Rationale: Turbidity measures suspended particles.
Correct Answer: B
10. Hardness in water is caused by:
A. Sodium and potassium
B. Calcium and magnesium
C. Chlorine
D. Iron only
Rationale: Hardness is due to calcium and magnesium ions.
Correct Answer: B
11. The main disinfectant in most water plants is:
A. Oxygen
B. Chlorine
C. Nitrogen
D. Hydrogen
Rationale: Chlorine is widely used due to effectiveness and
cost.
Correct Answer: B
