TEXAS WASTEWATER CLASS A EXAM 2025 –
PRACTICE QUESTIONS WITH ANSWERS &
RATIONALES
ABOUT THIS RESOURCE
This comprehensive practice exam is designed for candidates preparing for
the Texas Commission on Environmental Quality (TCEQ) Class A
Wastewater Treatment Facility Operator Certification Examination .
The exam is a 6-hour computer-based test covering advanced wastewater
treatment principles, plant operations, process control, laboratory analysis,
safety, regulations, calculations, collection systems, sludge handling,
disinfection, troubleshooting, and operational management.
The questions in this document are aligned with TCEQ standards and cover
the most frequently tested areas on the official exam.
SECTION 1: REGULATORY AGENCIES & BASIC
CONCEPTS (Questions 1–25)
Question 1: The name of the state agency responsible for enforcing
pollution control laws in Texas is:
A) Texas Department of State Health Services (DSHS)
B) Texas Commission on Environmental Quality (TCEQ)
,C) Texas Water Development Board (TWDB)
D) Environmental Protection Agency (EPA)
Correct Answer: B) Texas Commission on Environmental Quality
(TCEQ)
Rationale: The Texas Commission on Environmental Quality (TCEQ) is the
state agency responsible for enforcing pollution control laws, issuing
wastewater operator licenses, and regulating wastewater treatment facilities
in Texas. The EPA (D) is the federal agency that sets national standards.
Question 2: The term "pathogenic" means:
A) Capable of causing disease
B) Relating to plant growth
C) Referring to chemical treatment
D) Pertaining to water quality standards
Correct Answer: A) Capable of causing disease
Rationale: Pathogenic organisms are those that can cause disease in humans
or animals. Pathogenic bacteria, viruses, and parasites are a primary concern
in wastewater treatment and are targeted for removal or inactivation.
Question 3: What is the primary purpose of wastewater treatment?
A) To produce drinking water
B) To remove pollutants and protect public health and the environment
C) To generate electricity
D) To create fertilizer
,Correct Answer: B) To remove pollutants and protect public health and
the environment
Rationale: The primary purpose of wastewater treatment is to remove or
reduce pollutants (organic matter, solids, nutrients, pathogens) to levels that
protect public health and the receiving environment before discharge.
Question 4: Which federal agency sets national standards for wastewater
discharge?
A) Texas Commission on Environmental Quality (TCEQ)
B) Centers for Disease Control (CDC)
C) Environmental Protection Agency (EPA)
D) Occupational Safety and Health Administration (OSHA)
Correct Answer: C) Environmental Protection Agency (EPA)
Rationale: The EPA sets national standards for wastewater discharge through
the Clean Water Act, including effluent guidelines and water quality criteria.
TCEQ (A) enforces these standards at the state level.
Question 5: The term "eutrophication" in a pond system refers to:
A) Excessive nutrient enrichment leading to algae blooms
B) The process of settling solids
C) The removal of pathogens
D) The oxidation of organic matter
Correct Answer: A) Excessive nutrient enrichment leading to algae
blooms
, Rationale: Eutrophication is caused by excessive nutrients (primarily nitrogen
and phosphorus) entering a water body, leading to accelerated algae growth,
oxygen depletion, and degradation of water quality.
Question 6: When must TCEQ be notified about expansions of a treatment
facility?
A) Within 30 days after completion
B) Before construction begins
C) Within 60 days after completion
D) Only if the expansion exceeds 50% capacity
Correct Answer: B) Before construction begins
Rationale: TCEQ must be notified before construction begins on any
expansion or modification to a treatment facility. This allows the agency to
review plans and ensure compliance with permit requirements.
Question 7: The maximum contaminant level (MCL) for total coliform in
drinking water is:
A) 0 per 100 mL
B) 1 per 100 mL
C) 5 per 100 mL
D) 10 per 100 mL
Correct Answer: A) 0 per 100 mL
Rationale: The MCL for total coliform in drinking water is 0 per 100 mL. For
wastewater effluent, coliform limits are set by the discharge permit based on
the receiving water body.
PRACTICE QUESTIONS WITH ANSWERS &
RATIONALES
ABOUT THIS RESOURCE
This comprehensive practice exam is designed for candidates preparing for
the Texas Commission on Environmental Quality (TCEQ) Class A
Wastewater Treatment Facility Operator Certification Examination .
The exam is a 6-hour computer-based test covering advanced wastewater
treatment principles, plant operations, process control, laboratory analysis,
safety, regulations, calculations, collection systems, sludge handling,
disinfection, troubleshooting, and operational management.
The questions in this document are aligned with TCEQ standards and cover
the most frequently tested areas on the official exam.
SECTION 1: REGULATORY AGENCIES & BASIC
CONCEPTS (Questions 1–25)
Question 1: The name of the state agency responsible for enforcing
pollution control laws in Texas is:
A) Texas Department of State Health Services (DSHS)
B) Texas Commission on Environmental Quality (TCEQ)
,C) Texas Water Development Board (TWDB)
D) Environmental Protection Agency (EPA)
Correct Answer: B) Texas Commission on Environmental Quality
(TCEQ)
Rationale: The Texas Commission on Environmental Quality (TCEQ) is the
state agency responsible for enforcing pollution control laws, issuing
wastewater operator licenses, and regulating wastewater treatment facilities
in Texas. The EPA (D) is the federal agency that sets national standards.
Question 2: The term "pathogenic" means:
A) Capable of causing disease
B) Relating to plant growth
C) Referring to chemical treatment
D) Pertaining to water quality standards
Correct Answer: A) Capable of causing disease
Rationale: Pathogenic organisms are those that can cause disease in humans
or animals. Pathogenic bacteria, viruses, and parasites are a primary concern
in wastewater treatment and are targeted for removal or inactivation.
Question 3: What is the primary purpose of wastewater treatment?
A) To produce drinking water
B) To remove pollutants and protect public health and the environment
C) To generate electricity
D) To create fertilizer
,Correct Answer: B) To remove pollutants and protect public health and
the environment
Rationale: The primary purpose of wastewater treatment is to remove or
reduce pollutants (organic matter, solids, nutrients, pathogens) to levels that
protect public health and the receiving environment before discharge.
Question 4: Which federal agency sets national standards for wastewater
discharge?
A) Texas Commission on Environmental Quality (TCEQ)
B) Centers for Disease Control (CDC)
C) Environmental Protection Agency (EPA)
D) Occupational Safety and Health Administration (OSHA)
Correct Answer: C) Environmental Protection Agency (EPA)
Rationale: The EPA sets national standards for wastewater discharge through
the Clean Water Act, including effluent guidelines and water quality criteria.
TCEQ (A) enforces these standards at the state level.
Question 5: The term "eutrophication" in a pond system refers to:
A) Excessive nutrient enrichment leading to algae blooms
B) The process of settling solids
C) The removal of pathogens
D) The oxidation of organic matter
Correct Answer: A) Excessive nutrient enrichment leading to algae
blooms
, Rationale: Eutrophication is caused by excessive nutrients (primarily nitrogen
and phosphorus) entering a water body, leading to accelerated algae growth,
oxygen depletion, and degradation of water quality.
Question 6: When must TCEQ be notified about expansions of a treatment
facility?
A) Within 30 days after completion
B) Before construction begins
C) Within 60 days after completion
D) Only if the expansion exceeds 50% capacity
Correct Answer: B) Before construction begins
Rationale: TCEQ must be notified before construction begins on any
expansion or modification to a treatment facility. This allows the agency to
review plans and ensure compliance with permit requirements.
Question 7: The maximum contaminant level (MCL) for total coliform in
drinking water is:
A) 0 per 100 mL
B) 1 per 100 mL
C) 5 per 100 mL
D) 10 per 100 mL
Correct Answer: A) 0 per 100 mL
Rationale: The MCL for total coliform in drinking water is 0 per 100 mL. For
wastewater effluent, coliform limits are set by the discharge permit based on
the receiving water body.
