TCEQ Class D Water Operator License
Exam Questions with Correct Answers
Brand New 2026 Top Rated A+
modeled after common topics and real study materials. Class D is the
entry-level license in Texas for smaller systems (typically groundwater or
purchased water with limited connections).
1. In Texas, about 75% of all water is used for commercial, industrial, or
agricultural purposes.
A. True
B. False
Answer A True
Rationale: Agriculture alone accounts for a large portion (around 57%)
of water demand in Texas. Understanding water use patterns helps
operators plan for demand and conservation.
2. Water covers approximately ________ of Earth's surface.
A. 50%
,B. 71%
C. 85%
D. 25%
Answer B>> 71%
Rationale: This highlights the hydrologic cycle and why only a tiny
fraction of water is readily available freshwater (about 1% easily
accessible).
3. "Potable" water means water that is:
A. Safe to drink and has a measurable chlorine residual
B. Clear in appearance only
C. At neutral pH
D. From a groundwater source
Answer A
Rationale: Potable water must be safe (free of pathogens and harmful
contaminants) and palatable, with adequate disinfectant residual to
maintain quality in the distribution system.
4. The primary state regulator of public water systems in Texas is the:
A. EPA
,B. TCEQ
C. Texas Department of Health
D. Local city council
Answer B>> TCEQ
Rationale: The Texas Commission on Environmental Quality (TCEQ)
enforces drinking water standards under the Safe Drinking Water Act
(primacy from EPA).
5. The federal agency responsible for setting national drinking water
standards is the:
A. TCEQ
B. EPA
C. OSHA
D. CDC
Answer B>> EPA
Rationale: The EPA sets the Safe Drinking Water Act standards; states
like Texas implement and enforce them via primacy.
6. An alkaline or basic solution has a pH:
A. Less than 7
, B. Equal to 7
C. Greater than 7
D. Greater than 14
Answer C>> Greater than 7
Rationale: pH affects corrosion, disinfection efficiency, and taste. Texas
recommends slightly above 7 for non-corrosive water.
7. Pathogens are:
A. Disease-causing microorganisms
B. Chemicals that cause hardness
C. Suspended particles
D. Dissolved gases
Answer A
Rationale: Operators focus on destroying or removing pathogens
(bacteria, viruses, protozoa) through treatment and disinfection to
prevent waterborne disease.
8. When chlorine gas is used, a full-face self-contained breathing
apparatus (SCBA) must be readily accessible:
A. In the office
Exam Questions with Correct Answers
Brand New 2026 Top Rated A+
modeled after common topics and real study materials. Class D is the
entry-level license in Texas for smaller systems (typically groundwater or
purchased water with limited connections).
1. In Texas, about 75% of all water is used for commercial, industrial, or
agricultural purposes.
A. True
B. False
Answer A True
Rationale: Agriculture alone accounts for a large portion (around 57%)
of water demand in Texas. Understanding water use patterns helps
operators plan for demand and conservation.
2. Water covers approximately ________ of Earth's surface.
A. 50%
,B. 71%
C. 85%
D. 25%
Answer B>> 71%
Rationale: This highlights the hydrologic cycle and why only a tiny
fraction of water is readily available freshwater (about 1% easily
accessible).
3. "Potable" water means water that is:
A. Safe to drink and has a measurable chlorine residual
B. Clear in appearance only
C. At neutral pH
D. From a groundwater source
Answer A
Rationale: Potable water must be safe (free of pathogens and harmful
contaminants) and palatable, with adequate disinfectant residual to
maintain quality in the distribution system.
4. The primary state regulator of public water systems in Texas is the:
A. EPA
,B. TCEQ
C. Texas Department of Health
D. Local city council
Answer B>> TCEQ
Rationale: The Texas Commission on Environmental Quality (TCEQ)
enforces drinking water standards under the Safe Drinking Water Act
(primacy from EPA).
5. The federal agency responsible for setting national drinking water
standards is the:
A. TCEQ
B. EPA
C. OSHA
D. CDC
Answer B>> EPA
Rationale: The EPA sets the Safe Drinking Water Act standards; states
like Texas implement and enforce them via primacy.
6. An alkaline or basic solution has a pH:
A. Less than 7
, B. Equal to 7
C. Greater than 7
D. Greater than 14
Answer C>> Greater than 7
Rationale: pH affects corrosion, disinfection efficiency, and taste. Texas
recommends slightly above 7 for non-corrosive water.
7. Pathogens are:
A. Disease-causing microorganisms
B. Chemicals that cause hardness
C. Suspended particles
D. Dissolved gases
Answer A
Rationale: Operators focus on destroying or removing pathogens
(bacteria, viruses, protozoa) through treatment and disinfection to
prevent waterborne disease.
8. When chlorine gas is used, a full-face self-contained breathing
apparatus (SCBA) must be readily accessible:
A. In the office
