California Water Treatment Operator Grade 2 Practice Exam - 100 Questions AND
CORRECT ANSWERS GRADE A
**QUESTION 1:**
What is the primary purpose of coagulation in water treatment?
A) Remove dissolved gases
B) Neutralize acidity
C) Destabilize suspended particles
D) Kill microorganisms
**ANSWER:** C
**EXPLANATION:** Coagulation destabilizes suspended particles so they can clump
together during flocculation.
**QUESTION 2:**
Which California regulation establishes drinking water standards?
A) Title 17
B) Title 22
C) Title 27
D) Title 8
**ANSWER:** B
**EXPLANATION:** Title 22 of the California Code of Regulations contains drinking water
standards and requirements.
**QUESTION 3:**
What is the maximum contaminant level (MCL) for total coliform bacteria?
,A) 0 colonies/100 mL
B) 1 colony/100 mL
C) 5 colonies/100 mL
D) 10 colonies/100 mL
**ANSWER:** B
**EXPLANATION:** The MCL for total coliform is 1 colony per 100 mL (positive sample).
**QUESTION 4:**
Which chemical is commonly used for chlorine gas neutralization?
A) Sodium hydroxide
B) Sulfuric acid
C) Sodium thiosulfate
D) Sodium hypochlorite
**ANSWER:** A
**EXPLANATION:** Sodium hydroxide (caustic soda) is used to neutralize chlorine gas
leaks in scrubber systems.
**QUESTION 5:**
What is the purpose of a baffle wall in a sedimentation basin?
A) Increase velocity
B) Prevent short-circuiting
C) Add chlorine
D) Remove sludge
,**ANSWER:** B
**EXPLANATION:** Baffle walls prevent short-circuiting and improve flow distribution in
sedimentation basins.
**QUESTION 6:**
Which test measures the buffering capacity of water?
A) pH
B) Alkalinity
C) Hardness
D) Turbidity
**ANSWER:** B
**EXPLANATION:** Alkalinity measures water's capacity to neutralize acids (buffering
capacity).
**QUESTION 7:**
What is the minimum free chlorine residual required at the farthest point in the distribution
system?
A) 0.2 mg/L
B) 0.5 mg/L
C) 1.0 mg/L
D) 2.0 mg/L
**ANSWER:** A
**EXPLANATION:** California requires a minimum of 0.2 mg/L free chlorine residual
throughout the distribution system.
, **QUESTION 8:**
Which valve type is best for throttling flow?
A) Gate valve
B) Globe valve
C) Check valve
D) Butterfly valve
**ANSWER:** B
**EXPLANATION:** Globe valves are designed for throttling and regulating flow.
**QUESTION 9:**
What is the purpose of a surge tank in a water system?
A) Store treated water
B) Control water hammer
C) Add chemicals
D) Remove air
**ANSWER:** B
**EXPLANATION:** Surge tanks help control water hammer and pressure surges in
pipelines.
**QUESTION 10:**
Which pump type is most suitable for high-head, low-flow applications?
A) Centrifugal pump
B) Positive displacement pump
C) Turbine pump
CORRECT ANSWERS GRADE A
**QUESTION 1:**
What is the primary purpose of coagulation in water treatment?
A) Remove dissolved gases
B) Neutralize acidity
C) Destabilize suspended particles
D) Kill microorganisms
**ANSWER:** C
**EXPLANATION:** Coagulation destabilizes suspended particles so they can clump
together during flocculation.
**QUESTION 2:**
Which California regulation establishes drinking water standards?
A) Title 17
B) Title 22
C) Title 27
D) Title 8
**ANSWER:** B
**EXPLANATION:** Title 22 of the California Code of Regulations contains drinking water
standards and requirements.
**QUESTION 3:**
What is the maximum contaminant level (MCL) for total coliform bacteria?
,A) 0 colonies/100 mL
B) 1 colony/100 mL
C) 5 colonies/100 mL
D) 10 colonies/100 mL
**ANSWER:** B
**EXPLANATION:** The MCL for total coliform is 1 colony per 100 mL (positive sample).
**QUESTION 4:**
Which chemical is commonly used for chlorine gas neutralization?
A) Sodium hydroxide
B) Sulfuric acid
C) Sodium thiosulfate
D) Sodium hypochlorite
**ANSWER:** A
**EXPLANATION:** Sodium hydroxide (caustic soda) is used to neutralize chlorine gas
leaks in scrubber systems.
**QUESTION 5:**
What is the purpose of a baffle wall in a sedimentation basin?
A) Increase velocity
B) Prevent short-circuiting
C) Add chlorine
D) Remove sludge
,**ANSWER:** B
**EXPLANATION:** Baffle walls prevent short-circuiting and improve flow distribution in
sedimentation basins.
**QUESTION 6:**
Which test measures the buffering capacity of water?
A) pH
B) Alkalinity
C) Hardness
D) Turbidity
**ANSWER:** B
**EXPLANATION:** Alkalinity measures water's capacity to neutralize acids (buffering
capacity).
**QUESTION 7:**
What is the minimum free chlorine residual required at the farthest point in the distribution
system?
A) 0.2 mg/L
B) 0.5 mg/L
C) 1.0 mg/L
D) 2.0 mg/L
**ANSWER:** A
**EXPLANATION:** California requires a minimum of 0.2 mg/L free chlorine residual
throughout the distribution system.
, **QUESTION 8:**
Which valve type is best for throttling flow?
A) Gate valve
B) Globe valve
C) Check valve
D) Butterfly valve
**ANSWER:** B
**EXPLANATION:** Globe valves are designed for throttling and regulating flow.
**QUESTION 9:**
What is the purpose of a surge tank in a water system?
A) Store treated water
B) Control water hammer
C) Add chemicals
D) Remove air
**ANSWER:** B
**EXPLANATION:** Surge tanks help control water hammer and pressure surges in
pipelines.
**QUESTION 10:**
Which pump type is most suitable for high-head, low-flow applications?
A) Centrifugal pump
B) Positive displacement pump
C) Turbine pump
