TCEQ Class C Water License Exam
Actual Questions & Answers| Latest Update
Texas Commission on Environmental Quality (TCEQ)
,1. Which state agency is responsible for enforcing the Safe Drinking Water Act
and licensing water operators in Texas?
A. Texas Department of Health Services
B. Texas Commission on Environmental Quality (TCEQ)
C. Environmental Protection Agency (EPA) regional office only
D. Texas Water Development Board
Answer: B
Rationale: TCEQ is the primary state agency delegated authority (primacy) by
the EPA to implement and enforce the Safe Drinking Water Act in Texas,
including licensing water treatment and distribution operators.
2. A Class C Water License in Texas authorizes an operator to work at which type
of systems, based on classification?
A. Only the largest, most complex surface water systems
B. Smaller and less complex public water systems, per TCEQ system
classification criteria
C. Only wastewater treatment plants
D. Only irrigation systems
Answer: B
Rationale: TCEQ classifies water systems (A, B, C, D) by size and complexity; a
Class C license authorizes operation of smaller, less complex systems, while
larger/more complex systems require higher classifications (B or A).
3. At all times, a public water system must provide customers with:
A. The lowest possible cost water regardless of quality
B. An adequate quantity of water at adequate pressure, that is properly
disinfected
C. Water only during business hours
D. Untreated raw water for irrigation use only
Answer: B
Rationale: A fundamental duty of a public water system is to continuously
supply an adequate quantity of water, at adequate pressure, that has been
properly treated and disinfected to protect public health.
4. Which of the following minerals are the primary cause of water hardness?
, A. Sodium and potassium
B. Calcium and magnesium
C. Iron and manganese only
D. Chlorine and fluoride
Answer: B
Rationale: Water hardness is primarily caused by dissolved calcium and
magnesium ions, which can cause scaling in pipes and reduce soap/detergent
effectiveness.
5. A groundwater source typically refers to water obtained from:
A. Lakes and reservoirs only
B. An aquifer via wells
C. Rainwater collection tanks
D. Rivers only
Answer: B
Rationale: Groundwater sources are drawn from aquifers—underground layers
of water-bearing permeable rock or sediment—accessed through wells,
distinguishing them from surface water sources like lakes and rivers.
6. The presence of fecal coliform organisms in a water supply indicates:
A. The water is perfectly safe and requires no action
B. Possible contamination and the potential presence of pathogenic (disease-
causing) organisms
C. The water has too much chlorine
D. The water is naturally hard
Answer: B
Rationale: Fecal coliform bacteria serve as indicator organisms; their presence
suggests fecal contamination and the possible presence of harmful pathogens,
signaling the water may be unsafe for consumption.
7. Dysentery is an example of a disease that can be spread by:
A. Properly chlorinated drinking water
B. Inadequately disinfected water contaminated with pathogens
C. Water with excessive fluoride
, D. Water with high hardness
Answer: B
Rationale: Dysentery and other waterborne illnesses are typically spread
through water that has not been adequately disinfected, allowing disease-
causing microorganisms to persist and be ingested by consumers.
8. A common and cost-effective chemical used for disinfection in small water
supply systems is:
A. Sodium fluoride
B. Calcium hypochlorite
C. Potassium permanganate only
D. Activated carbon
Answer: B
Rationale: Calcium hypochlorite (a solid chlorine compound) is widely used in
small systems for disinfection due to its stability, ease of storage, and
effectiveness at inactivating pathogens.
9. A cross connection is best described as:
A. A backup generator connection
B. A physical connection between a potable water supply and a source of
contamination or non-potable water
C. A junction of two water mains of the same utility
D. A meter connection at a customer's property
Answer: B
Rationale: A cross connection is any actual or potential physical link between a
safe drinking water system and a source of contamination (such as a private
well, irrigation system, or industrial process), creating backflow risk.
10. The amount of chlorine consumed by reacting with iron, organics, and
microorganisms in water before a residual remains is called:
A. Chlorine residual
B. Chlorine demand
C. Chlorine dosage
D. Breakpoint chlorination
Actual Questions & Answers| Latest Update
Texas Commission on Environmental Quality (TCEQ)
,1. Which state agency is responsible for enforcing the Safe Drinking Water Act
and licensing water operators in Texas?
A. Texas Department of Health Services
B. Texas Commission on Environmental Quality (TCEQ)
C. Environmental Protection Agency (EPA) regional office only
D. Texas Water Development Board
Answer: B
Rationale: TCEQ is the primary state agency delegated authority (primacy) by
the EPA to implement and enforce the Safe Drinking Water Act in Texas,
including licensing water treatment and distribution operators.
2. A Class C Water License in Texas authorizes an operator to work at which type
of systems, based on classification?
A. Only the largest, most complex surface water systems
B. Smaller and less complex public water systems, per TCEQ system
classification criteria
C. Only wastewater treatment plants
D. Only irrigation systems
Answer: B
Rationale: TCEQ classifies water systems (A, B, C, D) by size and complexity; a
Class C license authorizes operation of smaller, less complex systems, while
larger/more complex systems require higher classifications (B or A).
3. At all times, a public water system must provide customers with:
A. The lowest possible cost water regardless of quality
B. An adequate quantity of water at adequate pressure, that is properly
disinfected
C. Water only during business hours
D. Untreated raw water for irrigation use only
Answer: B
Rationale: A fundamental duty of a public water system is to continuously
supply an adequate quantity of water, at adequate pressure, that has been
properly treated and disinfected to protect public health.
4. Which of the following minerals are the primary cause of water hardness?
, A. Sodium and potassium
B. Calcium and magnesium
C. Iron and manganese only
D. Chlorine and fluoride
Answer: B
Rationale: Water hardness is primarily caused by dissolved calcium and
magnesium ions, which can cause scaling in pipes and reduce soap/detergent
effectiveness.
5. A groundwater source typically refers to water obtained from:
A. Lakes and reservoirs only
B. An aquifer via wells
C. Rainwater collection tanks
D. Rivers only
Answer: B
Rationale: Groundwater sources are drawn from aquifers—underground layers
of water-bearing permeable rock or sediment—accessed through wells,
distinguishing them from surface water sources like lakes and rivers.
6. The presence of fecal coliform organisms in a water supply indicates:
A. The water is perfectly safe and requires no action
B. Possible contamination and the potential presence of pathogenic (disease-
causing) organisms
C. The water has too much chlorine
D. The water is naturally hard
Answer: B
Rationale: Fecal coliform bacteria serve as indicator organisms; their presence
suggests fecal contamination and the possible presence of harmful pathogens,
signaling the water may be unsafe for consumption.
7. Dysentery is an example of a disease that can be spread by:
A. Properly chlorinated drinking water
B. Inadequately disinfected water contaminated with pathogens
C. Water with excessive fluoride
, D. Water with high hardness
Answer: B
Rationale: Dysentery and other waterborne illnesses are typically spread
through water that has not been adequately disinfected, allowing disease-
causing microorganisms to persist and be ingested by consumers.
8. A common and cost-effective chemical used for disinfection in small water
supply systems is:
A. Sodium fluoride
B. Calcium hypochlorite
C. Potassium permanganate only
D. Activated carbon
Answer: B
Rationale: Calcium hypochlorite (a solid chlorine compound) is widely used in
small systems for disinfection due to its stability, ease of storage, and
effectiveness at inactivating pathogens.
9. A cross connection is best described as:
A. A backup generator connection
B. A physical connection between a potable water supply and a source of
contamination or non-potable water
C. A junction of two water mains of the same utility
D. A meter connection at a customer's property
Answer: B
Rationale: A cross connection is any actual or potential physical link between a
safe drinking water system and a source of contamination (such as a private
well, irrigation system, or industrial process), creating backflow risk.
10. The amount of chlorine consumed by reacting with iron, organics, and
microorganisms in water before a residual remains is called:
A. Chlorine residual
B. Chlorine demand
C. Chlorine dosage
D. Breakpoint chlorination
