TCEQ CLASS C WATER LICENSE EXAM – COMPLETE EXAM QUESTIONS
& VERIFIED ANSWERS | TEXAS COMMISSION ON ENVIRONMENTAL
QUALITY (TCEQ) | 2026/2027 UPDATE
1. When treating surface water, the process of coagulation is most
affected by which of the following?
A. Pressure, hardness, acidity, and oxygen levels
B. pH, alkalinity, temperature, and chemical dosage
C. Density, viscosity, color, and mineral content
D. Temperature, turbidity, salinity, and flow rate
Correct Answer: B
Rationale: Coagulation effectiveness is primarily determined by pH,
alkalinity, temperature, and the dosage of coagulant chemicals. These
factors control how well the coagulant destabilizes suspended particles.
Pressure, hardness, and density are not the primary controlling factors.
2. A newly hired water-system operator is preparing to work toward a
TCEQ Class C water operator license. Which statement best describes
why the operator should first identify the specific type of Class C
license being pursued?
A. All Class C water licenses have exactly the same training and technical
knowledge requirements
B. The operator must select the applicable field because Class C
licensing includes distinct Groundwater, Surface Water, and Water
Distribution pathways with different technical training requirements
C. Only Surface Water operators are required to complete an
examination
,D. A Class C applicant can obtain any water operator license without
field-specific experience or training
Correct Answer: B
Rationale: TCEQ identifies separate Class C licensing pathways for
Groundwater, Surface Water, and Water Distribution. Each pathway has
its own required technical training and knowledge areas, so the
applicant must first determine the specific license type that
corresponds to the work being performed.
3. Water that is considered neutral is expressed on the pH scale at
which value?
A. 6.0
B. 5.5
C. 8.0
D. 7.0
Correct Answer: D
Rationale: A pH of 7.0 is neutral. Values below 7.0 are acidic, and values
above 7.0 are basic (alkaline). This is a fundamental water chemistry
concept tested on the TCEQ Class C exam.
4. The results of bacteriological analysis shall be kept on file and
available for how many years?
A. 7
B. 4
C. 5
D. 24
Correct Answer: C
Rationale: Bacteriological analysis records must be kept on file for 5
years per TCEQ requirements under 30 TAC Chapter 290. Proper record
,retention is a core regulatory requirement for all public water system
operators.
5. One horsepower (1 hp) is equal to how many foot-pounds of force
per minute?
A. 30,000 foot-pounds
B. 40,000 foot-pounds
C. 33,000 foot-pounds
D. 25,000 foot-pounds
Correct Answer: C
Rationale: One horsepower equals 33,000 foot-pounds of work per
minute. This conversion factor is commonly used in pump and motor
calculations on the TCEQ Class C licensing exam.
6. Excess fluoride in water may be removed by which of the following
treatment methods?
A. Potassium permanganate
B. Free available chlorine
C. Activated alumina
D. Calcium chloride
Correct Answer: C
Rationale: Activated alumina is commonly used to remove excess
fluoride from drinking water through adsorption. The other chemicals
listed serve different treatment purposes: potassium permanganate is
for oxidation, chlorine is for disinfection, and calcium chloride is for
hardness adjustment.
7. The top of a pipe in a trench must be at least how many inches from
the top of the ground?
A. 24
, B. 35
C. 5
D. 500
Correct Answer: A
Rationale: The top of a pipe must be at least 24 inches below the
ground surface to protect it from freezing and physical damage. This is a
standard TCEQ requirement for water main installation.
8. Using a ton cylinder, the maximum withdrawal rate of chlorine
should not exceed which amount?
A. 600 pounds
B. 500 pounds
C. 400 pounds
D. 300 pounds
Correct Answer: B
Rationale: The maximum withdrawal rate from a ton cylinder is 500
pounds per day to prevent freezing of the chlorine and ensure safe
operation. Exceeding this rate can cause the cylinder to freeze and
disrupt chemical feed systems.
9. Trihalomethanes (THMs) are formed by the reaction of which
substance with organic chemicals?
A. Free available chlorine
B. Ultraviolet radiation
C. Chlorine dioxide
D. Ozone
Correct Answer: A
Rationale: Trihalomethanes (THMs) are disinfection byproducts formed
when free available chlorine reacts with natural organic matter in water.
& VERIFIED ANSWERS | TEXAS COMMISSION ON ENVIRONMENTAL
QUALITY (TCEQ) | 2026/2027 UPDATE
1. When treating surface water, the process of coagulation is most
affected by which of the following?
A. Pressure, hardness, acidity, and oxygen levels
B. pH, alkalinity, temperature, and chemical dosage
C. Density, viscosity, color, and mineral content
D. Temperature, turbidity, salinity, and flow rate
Correct Answer: B
Rationale: Coagulation effectiveness is primarily determined by pH,
alkalinity, temperature, and the dosage of coagulant chemicals. These
factors control how well the coagulant destabilizes suspended particles.
Pressure, hardness, and density are not the primary controlling factors.
2. A newly hired water-system operator is preparing to work toward a
TCEQ Class C water operator license. Which statement best describes
why the operator should first identify the specific type of Class C
license being pursued?
A. All Class C water licenses have exactly the same training and technical
knowledge requirements
B. The operator must select the applicable field because Class C
licensing includes distinct Groundwater, Surface Water, and Water
Distribution pathways with different technical training requirements
C. Only Surface Water operators are required to complete an
examination
,D. A Class C applicant can obtain any water operator license without
field-specific experience or training
Correct Answer: B
Rationale: TCEQ identifies separate Class C licensing pathways for
Groundwater, Surface Water, and Water Distribution. Each pathway has
its own required technical training and knowledge areas, so the
applicant must first determine the specific license type that
corresponds to the work being performed.
3. Water that is considered neutral is expressed on the pH scale at
which value?
A. 6.0
B. 5.5
C. 8.0
D. 7.0
Correct Answer: D
Rationale: A pH of 7.0 is neutral. Values below 7.0 are acidic, and values
above 7.0 are basic (alkaline). This is a fundamental water chemistry
concept tested on the TCEQ Class C exam.
4. The results of bacteriological analysis shall be kept on file and
available for how many years?
A. 7
B. 4
C. 5
D. 24
Correct Answer: C
Rationale: Bacteriological analysis records must be kept on file for 5
years per TCEQ requirements under 30 TAC Chapter 290. Proper record
,retention is a core regulatory requirement for all public water system
operators.
5. One horsepower (1 hp) is equal to how many foot-pounds of force
per minute?
A. 30,000 foot-pounds
B. 40,000 foot-pounds
C. 33,000 foot-pounds
D. 25,000 foot-pounds
Correct Answer: C
Rationale: One horsepower equals 33,000 foot-pounds of work per
minute. This conversion factor is commonly used in pump and motor
calculations on the TCEQ Class C licensing exam.
6. Excess fluoride in water may be removed by which of the following
treatment methods?
A. Potassium permanganate
B. Free available chlorine
C. Activated alumina
D. Calcium chloride
Correct Answer: C
Rationale: Activated alumina is commonly used to remove excess
fluoride from drinking water through adsorption. The other chemicals
listed serve different treatment purposes: potassium permanganate is
for oxidation, chlorine is for disinfection, and calcium chloride is for
hardness adjustment.
7. The top of a pipe in a trench must be at least how many inches from
the top of the ground?
A. 24
, B. 35
C. 5
D. 500
Correct Answer: A
Rationale: The top of a pipe must be at least 24 inches below the
ground surface to protect it from freezing and physical damage. This is a
standard TCEQ requirement for water main installation.
8. Using a ton cylinder, the maximum withdrawal rate of chlorine
should not exceed which amount?
A. 600 pounds
B. 500 pounds
C. 400 pounds
D. 300 pounds
Correct Answer: B
Rationale: The maximum withdrawal rate from a ton cylinder is 500
pounds per day to prevent freezing of the chlorine and ensure safe
operation. Exceeding this rate can cause the cylinder to freeze and
disrupt chemical feed systems.
9. Trihalomethanes (THMs) are formed by the reaction of which
substance with organic chemicals?
A. Free available chlorine
B. Ultraviolet radiation
C. Chlorine dioxide
D. Ozone
Correct Answer: A
Rationale: Trihalomethanes (THMs) are disinfection byproducts formed
when free available chlorine reacts with natural organic matter in water.
