TCEQ Class A Water Exam | Comprehensive Practice
Exam with Actual Exam Questions, Verified Correct
Answers and Detailed Rationales | Latest Update
2026/2027 - Graded A+
Question 1
How long must Monthly Operating Reports (MORs) be kept?
A. 5 years
B. 1 year
C. 25 years
D. 10 years
Answer: A
Rationale: Monthly Operating Reports (MORs) must be kept for a minimum of 5 years.
These records document plant operations, chemical usage, water quality parameters, and
compliance with regulatory requirements.
Question 2
When does total hardness equal total alkalinity?
A. When all hardness is carbonate hardness
B. When the pH is exactly 7.0
C. When all hardness is non-carbonate hardness
D. When the water is supersaturated with calcium
Answer: A
Rationale: Total hardness equals total alkalinity when all hardness is carbonate hardness.
This occurs when the hardness is primarily from calcium and magnesium carbonates, and
there is no non-carbonate hardness from sulfates, chlorides, or nitrates.
Question 3
What happens when groundwater with free chlorine blends with chloraminated water?
A. They form a stable compound that increases disinfection efficiency
B. They neutralize each other, resulting in pure water
C. They react, forming dichloramine - can cause taste and odor issues
D. They cause the groundwater to become more alkaline
Answer: C
Rationale: When groundwater with free chlorine blends with chloraminated water, they
react to form dichloramine, which can cause taste and odor issues. This reaction can also
reduce the effectiveness of the disinfection process.
pg. 1
,Question 4
What respiratory equipment protects from oxygen-deficient atmospheres?
A. A self-contained breathing apparatus
B. Air-purifying respirator (APR)
C. Escape hood
D. SCBA or supplied-air respirator
Answer: D
Rationale: Self-contained breathing apparatus (SCBA) or supplied-air respirators are
required for protection in oxygen-deficient atmospheres (less than 19.5% oxygen). Air-
purifying respirators do not provide oxygen and are ineffective in oxygen-deficient
environments.
Question 5
How long must bacteriological analysis results be retained?
A. 5 years
B. Indefinitely
C. 10 years
D. 1 year
Answer: A
Rationale: Bacteriological analysis results must be retained for 5 years. These records
document water quality testing and compliance with drinking water standards.
Question 6
What are signs of nitrification?
A. Decrease in pH and increase in dissolved oxygen levels
B. Increase in total chlorine residual and presence of ammonia
C. Loss of total chlorine residual, presence of nitrite or nitrate
D. Formation of trihalomethanes and haloacetic acids
Answer: C
Rationale: Signs of nitrification include loss of total chlorine residual and the presence
of nitrite or nitrate. Nitrification is a biological process in which ammonia is oxidized to
nitrite and then to nitrate, consuming chlorine and reducing disinfection effectiveness.
Question 7
What are the conditions for a hydrostatic leak test?
A. Test at 1.0 times the working pressure for 1 hour
B. Test at 0.5 times the working pressure for 30 minutes
C. Test at 1.5 times the working pressure for 2 hours
D. Test at 2.0 times the working pressure for 4 hours
Answer: C
pg. 2
,Rationale: A hydrostatic leak test should be conducted at 1.5 times the working pressure
for 2 hours to ensure the integrity of the piping system. This pressure test helps identify
leaks and weaknesses before placing the system into service.
Question 8
What is the correct order for testing hazardous atmospheres?
A. Oxygen, Combustibles, Toxic gases
B. Toxic gases, Oxygen, Combustibles
C. Combustibles, Oxygen, Toxic gases
D. Temperature and Dissolved oxygen
Answer: A
Rationale: The correct order for testing hazardous atmospheres is: Oxygen first (to
ensure sufficient oxygen for life), then Combustibles (to check for explosive hazards),
and finally Toxic gases (to check for harmful contaminants). This sequence prioritizes
life-safety and explosive hazards.
Question 9
When is removal of iron and manganese not required?
A. If sequestered and no discoloration exists in the distribution system
B. If the pH is adjusted to 8.5 or higher
C. If the water is being treated with activated carbon
D. If the concentration is below 0.05 mg/L
Answer: A
Rationale: Removal of iron and manganese is not required if they are sequestered (kept
in solution) and no discoloration exists in the distribution system. Sequestration prevents
staining and taste issues without removing the minerals.
Question 10
What certification ensures safety of water treatment chemicals?
A. They react, forming dichloramine - can cause taste and odor issues
B. [lbs active chem A + lbs active chem B) + total solution lbs] × 100
C. They must prevent accumulation of settled solids
D. ANSI/NSF Standard 60 (60 is for chemicals & 61 is for components)
Answer: D
Rationale: ANSI/NSF Standard 60 ensures the safety of water treatment chemicals.
Standard 60 applies to drinking water treatment chemicals, while Standard 61 applies to
component systems that contact drinking water.
Question 11
Should dead-end mains be included in sampling plans?
pg. 3
, A. Yes - blending ratio, source, and constituent calculations must be submitted
B. Cysts from protozoa entering via wastewater discharges
C. Yes - they must be sampled monthly because they are prone to low disinfectant
residuals and bacterial growth (30 TAC §290.109(c)(1)(A))
D. Savings = HP difference × 0.746 × Cost/kWh × Hours per year
Answer: C
Rationale: Dead-end mains must be included in sampling plans and sampled monthly
because they are prone to low disinfectant residuals and bacterial growth. This is required
by TCEQ regulations (30 TAC §290.109(c)(1)(A)).
Question 12
How effective is coagulation, flocculation, and settling at removing bacteria?
A. 35 ± 0.5°C (95°F)
B. Hydrogen sulfide
C. Removes 90% or more
D. Convert psi to feet (x2.31), then subtract pumping level from static level
Answer: C
Rationale: Coagulation, flocculation, and settling removes 90% or more of bacteria from
water. This process is highly effective at removing pathogens and other suspended solids.
Question 13
What should you do during a trench or cave-in emergency?
A. Call 911, Notify your supervisor immediately
B. Seal the trench immediately to prevent further collapse
C. Attempt to dig the person out yourself to save time
D. Wait for the fire department to arrive before doing anything
Answer: A
Rationale: During a trench or cave-in emergency, call 911 immediately and notify your
supervisor. Do not enter the trench yourself, as it could result in additional casualties.
Professional rescue personnel should handle the situation.
Question 14
What does aeration NOT do to help prevent TTHMs?
A. It can help to strip volatile organic compounds from the water
B. It does NOT remove precursors - only removes already formed TTHMs
C. It increases the dissolved oxygen in the water
D. It helps to oxidize organic precursors into less harmful compounds
Answer: B
Rationale: Aeration does NOT remove TTHM precursors - it only removes already
formed TTHMs. While aeration can help strip volatile organic compounds and increase
pg. 4
Exam with Actual Exam Questions, Verified Correct
Answers and Detailed Rationales | Latest Update
2026/2027 - Graded A+
Question 1
How long must Monthly Operating Reports (MORs) be kept?
A. 5 years
B. 1 year
C. 25 years
D. 10 years
Answer: A
Rationale: Monthly Operating Reports (MORs) must be kept for a minimum of 5 years.
These records document plant operations, chemical usage, water quality parameters, and
compliance with regulatory requirements.
Question 2
When does total hardness equal total alkalinity?
A. When all hardness is carbonate hardness
B. When the pH is exactly 7.0
C. When all hardness is non-carbonate hardness
D. When the water is supersaturated with calcium
Answer: A
Rationale: Total hardness equals total alkalinity when all hardness is carbonate hardness.
This occurs when the hardness is primarily from calcium and magnesium carbonates, and
there is no non-carbonate hardness from sulfates, chlorides, or nitrates.
Question 3
What happens when groundwater with free chlorine blends with chloraminated water?
A. They form a stable compound that increases disinfection efficiency
B. They neutralize each other, resulting in pure water
C. They react, forming dichloramine - can cause taste and odor issues
D. They cause the groundwater to become more alkaline
Answer: C
Rationale: When groundwater with free chlorine blends with chloraminated water, they
react to form dichloramine, which can cause taste and odor issues. This reaction can also
reduce the effectiveness of the disinfection process.
pg. 1
,Question 4
What respiratory equipment protects from oxygen-deficient atmospheres?
A. A self-contained breathing apparatus
B. Air-purifying respirator (APR)
C. Escape hood
D. SCBA or supplied-air respirator
Answer: D
Rationale: Self-contained breathing apparatus (SCBA) or supplied-air respirators are
required for protection in oxygen-deficient atmospheres (less than 19.5% oxygen). Air-
purifying respirators do not provide oxygen and are ineffective in oxygen-deficient
environments.
Question 5
How long must bacteriological analysis results be retained?
A. 5 years
B. Indefinitely
C. 10 years
D. 1 year
Answer: A
Rationale: Bacteriological analysis results must be retained for 5 years. These records
document water quality testing and compliance with drinking water standards.
Question 6
What are signs of nitrification?
A. Decrease in pH and increase in dissolved oxygen levels
B. Increase in total chlorine residual and presence of ammonia
C. Loss of total chlorine residual, presence of nitrite or nitrate
D. Formation of trihalomethanes and haloacetic acids
Answer: C
Rationale: Signs of nitrification include loss of total chlorine residual and the presence
of nitrite or nitrate. Nitrification is a biological process in which ammonia is oxidized to
nitrite and then to nitrate, consuming chlorine and reducing disinfection effectiveness.
Question 7
What are the conditions for a hydrostatic leak test?
A. Test at 1.0 times the working pressure for 1 hour
B. Test at 0.5 times the working pressure for 30 minutes
C. Test at 1.5 times the working pressure for 2 hours
D. Test at 2.0 times the working pressure for 4 hours
Answer: C
pg. 2
,Rationale: A hydrostatic leak test should be conducted at 1.5 times the working pressure
for 2 hours to ensure the integrity of the piping system. This pressure test helps identify
leaks and weaknesses before placing the system into service.
Question 8
What is the correct order for testing hazardous atmospheres?
A. Oxygen, Combustibles, Toxic gases
B. Toxic gases, Oxygen, Combustibles
C. Combustibles, Oxygen, Toxic gases
D. Temperature and Dissolved oxygen
Answer: A
Rationale: The correct order for testing hazardous atmospheres is: Oxygen first (to
ensure sufficient oxygen for life), then Combustibles (to check for explosive hazards),
and finally Toxic gases (to check for harmful contaminants). This sequence prioritizes
life-safety and explosive hazards.
Question 9
When is removal of iron and manganese not required?
A. If sequestered and no discoloration exists in the distribution system
B. If the pH is adjusted to 8.5 or higher
C. If the water is being treated with activated carbon
D. If the concentration is below 0.05 mg/L
Answer: A
Rationale: Removal of iron and manganese is not required if they are sequestered (kept
in solution) and no discoloration exists in the distribution system. Sequestration prevents
staining and taste issues without removing the minerals.
Question 10
What certification ensures safety of water treatment chemicals?
A. They react, forming dichloramine - can cause taste and odor issues
B. [lbs active chem A + lbs active chem B) + total solution lbs] × 100
C. They must prevent accumulation of settled solids
D. ANSI/NSF Standard 60 (60 is for chemicals & 61 is for components)
Answer: D
Rationale: ANSI/NSF Standard 60 ensures the safety of water treatment chemicals.
Standard 60 applies to drinking water treatment chemicals, while Standard 61 applies to
component systems that contact drinking water.
Question 11
Should dead-end mains be included in sampling plans?
pg. 3
, A. Yes - blending ratio, source, and constituent calculations must be submitted
B. Cysts from protozoa entering via wastewater discharges
C. Yes - they must be sampled monthly because they are prone to low disinfectant
residuals and bacterial growth (30 TAC §290.109(c)(1)(A))
D. Savings = HP difference × 0.746 × Cost/kWh × Hours per year
Answer: C
Rationale: Dead-end mains must be included in sampling plans and sampled monthly
because they are prone to low disinfectant residuals and bacterial growth. This is required
by TCEQ regulations (30 TAC §290.109(c)(1)(A)).
Question 12
How effective is coagulation, flocculation, and settling at removing bacteria?
A. 35 ± 0.5°C (95°F)
B. Hydrogen sulfide
C. Removes 90% or more
D. Convert psi to feet (x2.31), then subtract pumping level from static level
Answer: C
Rationale: Coagulation, flocculation, and settling removes 90% or more of bacteria from
water. This process is highly effective at removing pathogens and other suspended solids.
Question 13
What should you do during a trench or cave-in emergency?
A. Call 911, Notify your supervisor immediately
B. Seal the trench immediately to prevent further collapse
C. Attempt to dig the person out yourself to save time
D. Wait for the fire department to arrive before doing anything
Answer: A
Rationale: During a trench or cave-in emergency, call 911 immediately and notify your
supervisor. Do not enter the trench yourself, as it could result in additional casualties.
Professional rescue personnel should handle the situation.
Question 14
What does aeration NOT do to help prevent TTHMs?
A. It can help to strip volatile organic compounds from the water
B. It does NOT remove precursors - only removes already formed TTHMs
C. It increases the dissolved oxygen in the water
D. It helps to oxidize organic precursors into less harmful compounds
Answer: B
Rationale: Aeration does NOT remove TTHM precursors - it only removes already
formed TTHMs. While aeration can help strip volatile organic compounds and increase
pg. 4
