Texas Class B Water Operator certification
Real Exam With Actual Questions &
Verified Answers,Plus Rationales/Expert
Verified For Guaranteed Pass 2025/2026
/Latest Update/Instant Download Pdf
1. What is the primary purpose of coagulation in surface water treatment?
• A. Disinfect the water
• B. Adjust the pH
• C. Remove dissolved gases
• D. Destabilize suspended particles
Answer: D. Destabilize suspended particles
Rationale: Coagulation destabilizes fine particles, allowing them to aggregate into larger
flocs for easier removal during sedimentation and filtration.
2. Which chemical is commonly used as a coagulant in surface water treatment?
• A. Sodium hypochlorite
• B. Aluminum sulfate
• C. Lime
• D. Carbon dioxide
Answer: B. Aluminum sulfate
Rationale: Aluminum sulfate (alum) is widely used to remove turbidity and color from water
by aiding in coagulation.
3. The minimum free chlorine residual required at the entry point to the distribution
system is:
• A. 0.2 mg/L
, • B. 1.0 mg/L
• C. 0.5 mg/L
• D. 2.0 mg/L
Answer: B. 1.0 mg/L
Rationale: TCEQ regulations mandate a minimum free chlorine residual of 1.0 mg/L at the
entry point to ensure effective disinfection.
4. What is the purpose of sedimentation in the treatment process?
• A. Remove dissolved solids
• B. Remove suspended solids
• C. Disinfect the water
• D. Adjust the pH
Answer: B. Remove suspended solids
Rationale: Sedimentation allows heavier particles to settle, removing suspended solids
before filtration.
5. Which of the following is a common disinfectant used in water treatment?
• A. Sodium bicarbonate
• B. Chlorine
• C. Potassium permanganate
• D. Calcium carbonate
Answer: B. Chlorine
Rationale: Chlorine is commonly used for disinfection due to its effectiveness in killing
pathogens and residual disinfectant properties.
6. What is the typical pH range for potable water?
• A. 4.0 - 5.0
• B. 5.0 - 6.0
• C. 6.5 - 8.5
• D. 8.5 - 9.5
, Answer: C. 6.5 - 8.5
Rationale: A pH range of 6.5 to 8.5 is considered optimal for potable water, balancing
corrosion control and taste.
7. Which of the following is an indicator of the effectiveness of coagulation?
• A. pH level
• B. Turbidity
• C. Floc formation
• D. Chlorine residual
Answer: C. Floc formation
Rationale: Effective coagulation leads to the formation of flocs, which can then be removed
through sedimentation and filtration.
8. What is the primary function of a rapid sand filter?
• A. Coagulation
• B. Sedimentation
• C. Filtration
• D. Disinfection
Answer: C. Filtration
Rationale: Rapid sand filters are designed to remove suspended solids from water through a
bed of sand.
9. Which of the following is a sign of filter breakthrough?
• A. Increased turbidity in the effluent
• B. Decreased flow rate
• C. Increased chlorine demand
• D. Decreased pH
Answer: A. Increased turbidity in the effluent
Rationale: Filter breakthrough occurs when the filter media becomes clogged, allowing
particles to pass through and increase turbidity.
Real Exam With Actual Questions &
Verified Answers,Plus Rationales/Expert
Verified For Guaranteed Pass 2025/2026
/Latest Update/Instant Download Pdf
1. What is the primary purpose of coagulation in surface water treatment?
• A. Disinfect the water
• B. Adjust the pH
• C. Remove dissolved gases
• D. Destabilize suspended particles
Answer: D. Destabilize suspended particles
Rationale: Coagulation destabilizes fine particles, allowing them to aggregate into larger
flocs for easier removal during sedimentation and filtration.
2. Which chemical is commonly used as a coagulant in surface water treatment?
• A. Sodium hypochlorite
• B. Aluminum sulfate
• C. Lime
• D. Carbon dioxide
Answer: B. Aluminum sulfate
Rationale: Aluminum sulfate (alum) is widely used to remove turbidity and color from water
by aiding in coagulation.
3. The minimum free chlorine residual required at the entry point to the distribution
system is:
• A. 0.2 mg/L
, • B. 1.0 mg/L
• C. 0.5 mg/L
• D. 2.0 mg/L
Answer: B. 1.0 mg/L
Rationale: TCEQ regulations mandate a minimum free chlorine residual of 1.0 mg/L at the
entry point to ensure effective disinfection.
4. What is the purpose of sedimentation in the treatment process?
• A. Remove dissolved solids
• B. Remove suspended solids
• C. Disinfect the water
• D. Adjust the pH
Answer: B. Remove suspended solids
Rationale: Sedimentation allows heavier particles to settle, removing suspended solids
before filtration.
5. Which of the following is a common disinfectant used in water treatment?
• A. Sodium bicarbonate
• B. Chlorine
• C. Potassium permanganate
• D. Calcium carbonate
Answer: B. Chlorine
Rationale: Chlorine is commonly used for disinfection due to its effectiveness in killing
pathogens and residual disinfectant properties.
6. What is the typical pH range for potable water?
• A. 4.0 - 5.0
• B. 5.0 - 6.0
• C. 6.5 - 8.5
• D. 8.5 - 9.5
, Answer: C. 6.5 - 8.5
Rationale: A pH range of 6.5 to 8.5 is considered optimal for potable water, balancing
corrosion control and taste.
7. Which of the following is an indicator of the effectiveness of coagulation?
• A. pH level
• B. Turbidity
• C. Floc formation
• D. Chlorine residual
Answer: C. Floc formation
Rationale: Effective coagulation leads to the formation of flocs, which can then be removed
through sedimentation and filtration.
8. What is the primary function of a rapid sand filter?
• A. Coagulation
• B. Sedimentation
• C. Filtration
• D. Disinfection
Answer: C. Filtration
Rationale: Rapid sand filters are designed to remove suspended solids from water through a
bed of sand.
9. Which of the following is a sign of filter breakthrough?
• A. Increased turbidity in the effluent
• B. Decreased flow rate
• C. Increased chlorine demand
• D. Decreased pH
Answer: A. Increased turbidity in the effluent
Rationale: Filter breakthrough occurs when the filter media becomes clogged, allowing
particles to pass through and increase turbidity.
