Texas Water Operator Certification
Practice Exam Questions And Correct
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Rationales |2026 Q&A | Instant
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1. What is the primary purpose of chlorine in water treatment?
A. Soften the water
B. Disinfect the water
C. Remove turbidity
D. Increase alkalinity
Chlorine is used to kill or inactivate harmful microorganisms in
drinking water.
2. What is the minimum chlorine residual required in the distribution
system in Texas?
A. 0.1 mg/L
B. 0.5 mg/L
C. 0.2 mg/L
D. 1.0 mg/L
Texas regulations require a minimum free chlorine residual of 0.2
mg/L in the distribution system to ensure disinfection.
,3. Which chemical is commonly used to adjust pH in water treatment?
A. Chlorine
B. Lime
C. Aluminum sulfate
D. Fluoride
Lime is often used to raise the pH in water treatment systems.
4. What does NTU stand for?
A. Normal Turbidity Unit
B. Non-Toxic Unit
C. Nephelometric Turbidity Unit
D. Neutral Titration Unit
NTU is a measure of turbidity using a nephelometric method.
5. The Safe Drinking Water Act is enforced by:
A. U.S. Environmental Protection Agency
B. Texas Water Development Board
C. OSHA
D. USDA
The EPA enforces the Safe Drinking Water Act to ensure safe public
drinking water.
6. What is the typical pressure range in a municipal water distribution
system?
A. 10–30 psi
B. 30–50 psi
C. 35–100 psi
D. 90–150 psi
A typical system operates between 35 and 100 psi to ensure proper
flow and prevent backflow.
7. Which of the following is a coagulant?
A. Lime
, B. Soda ash
C. Chlorine
D. Aluminum sulfate
Aluminum sulfate (alum) is used in coagulation to bind particles for
removal.
8. What is the term for water that has no measurable chlorine residual?
A. Safe water
B. Dead water
C. Treated water
D. Turbid water
Dead water contains no disinfectant residual and poses a
contamination risk.
9. What is the primary source of coliform bacteria in water?
A. Industrial waste
B. Rainwater
C. Fecal contamination
D. Chlorine decay
Coliform bacteria are indicators of fecal contamination and potential
pathogens.
10. What is the main cause of water hammer?
A. Poor water quality
B. Low system pressure
C. Sudden change in water flow velocity
D. Leaking valves
Water hammer occurs when a valve closes suddenly, causing a
pressure surge.
11. What type of valve is typically used to isolate sections of water
mains?
A. Air release valve
Practice Exam Questions And Correct
Answers (Verified Answers) Plus
Rationales |2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of chlorine in water treatment?
A. Soften the water
B. Disinfect the water
C. Remove turbidity
D. Increase alkalinity
Chlorine is used to kill or inactivate harmful microorganisms in
drinking water.
2. What is the minimum chlorine residual required in the distribution
system in Texas?
A. 0.1 mg/L
B. 0.5 mg/L
C. 0.2 mg/L
D. 1.0 mg/L
Texas regulations require a minimum free chlorine residual of 0.2
mg/L in the distribution system to ensure disinfection.
,3. Which chemical is commonly used to adjust pH in water treatment?
A. Chlorine
B. Lime
C. Aluminum sulfate
D. Fluoride
Lime is often used to raise the pH in water treatment systems.
4. What does NTU stand for?
A. Normal Turbidity Unit
B. Non-Toxic Unit
C. Nephelometric Turbidity Unit
D. Neutral Titration Unit
NTU is a measure of turbidity using a nephelometric method.
5. The Safe Drinking Water Act is enforced by:
A. U.S. Environmental Protection Agency
B. Texas Water Development Board
C. OSHA
D. USDA
The EPA enforces the Safe Drinking Water Act to ensure safe public
drinking water.
6. What is the typical pressure range in a municipal water distribution
system?
A. 10–30 psi
B. 30–50 psi
C. 35–100 psi
D. 90–150 psi
A typical system operates between 35 and 100 psi to ensure proper
flow and prevent backflow.
7. Which of the following is a coagulant?
A. Lime
, B. Soda ash
C. Chlorine
D. Aluminum sulfate
Aluminum sulfate (alum) is used in coagulation to bind particles for
removal.
8. What is the term for water that has no measurable chlorine residual?
A. Safe water
B. Dead water
C. Treated water
D. Turbid water
Dead water contains no disinfectant residual and poses a
contamination risk.
9. What is the primary source of coliform bacteria in water?
A. Industrial waste
B. Rainwater
C. Fecal contamination
D. Chlorine decay
Coliform bacteria are indicators of fecal contamination and potential
pathogens.
10. What is the main cause of water hammer?
A. Poor water quality
B. Low system pressure
C. Sudden change in water flow velocity
D. Leaking valves
Water hammer occurs when a valve closes suddenly, causing a
pressure surge.
11. What type of valve is typically used to isolate sections of water
mains?
A. Air release valve
