Page 1 of 118
Texas Wastewater Collection System Operator Class II
Exam Questions with Correct Answers and explanations
LATEST THIS YEAR -JUST RELEASED
Texas Wastewater Collection System Operator Class II Exam
SUMMARIZED EXAM COVERAGE
The Texas Wastewater Collection System Operator Class II exam is administered by the Texas
Commission on Environmental Quality (TCEQ) and is a computer-based test (CBT) . Applicants must have
a high school diploma or GED and successfully complete a TCEQ-approved training course before
applying . The exam has a 3-hour time limit .
Key domains include: collection system operation & maintenance, hydraulics and flow velocity, lift
stations and pumps, safety and confined space entry, pipe materials and cleaning methods, inflow and
infiltration (I/I) identification and control, sewer rehabilitation and repair, regulations and emergency
response , laboratory procedures, and basic mathematics for operators.
1. What is the primary purpose of a wastewater collection system?
A) Treat wastewater before discharge
B) Disinfect effluent before discharge
C) Collect and transport wastewater to a treatment facility
D) Store drinking water for distribution
Answer: C
Rationale: The collection system's main function is to safely convey wastewater from homes,
businesses, and industries to a treatment plant, preventing environmental contamination .
, Page 2 of 118
2. Which of the following is the most common cause of sanitary sewer overflows (SSOs)?
A) Pump station electrical failure
B) Blockages due to grease, roots, and debris
C) Heavy rainfall only
D) Treatment plant bypass
Answer: B
Rationale: Grease, roots, and debris can obstruct pipes, causing backups and overflows in the system.
Regular cleaning and maintenance help prevent these blockages .
3. What type of pipe material is most resistant to root intrusion?
A) Clay pipe
B) PVC
C) Cast iron
D) Concrete pipe
Answer: B
, Page 3 of 118
Rationale: PVC pipes have smooth walls and tight joints, making it difficult for roots to penetrate
compared to older clay or concrete pipes with more joints .
4. What is the minimum slope recommended for a 4-inch diameter sewer pipe?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: B
Rationale: Adequate slope (typically 1/8 inch per foot for 4-inch pipe) ensures gravity flow without
causing sedimentation from excessive velocity or blockage from insufficient flow .
5. What is the purpose of a manhole in a collection system?
A) To increase flow velocity
B) To store sewage during peak flows
, Page 4 of 118
C) To provide access for inspection, maintenance, and flow measurement
D) To treat wastewater before discharge
Answer: C
Rationale: Manholes allow operators to inspect the system, remove blockages, and measure flow
without excavating the pipe .
6. Which gas is most commonly monitored in confined spaces in wastewater systems due to its toxicity
and flammability?
A) Carbon dioxide
B) Methane
C) Hydrogen sulfide (H₂S)
D) Nitrogen
Answer: C
Rationale: H₂S is toxic and flammable, produced by anaerobic decomposition of sewage. Monitoring is
essential to prevent worker injury or death .
Texas Wastewater Collection System Operator Class II
Exam Questions with Correct Answers and explanations
LATEST THIS YEAR -JUST RELEASED
Texas Wastewater Collection System Operator Class II Exam
SUMMARIZED EXAM COVERAGE
The Texas Wastewater Collection System Operator Class II exam is administered by the Texas
Commission on Environmental Quality (TCEQ) and is a computer-based test (CBT) . Applicants must have
a high school diploma or GED and successfully complete a TCEQ-approved training course before
applying . The exam has a 3-hour time limit .
Key domains include: collection system operation & maintenance, hydraulics and flow velocity, lift
stations and pumps, safety and confined space entry, pipe materials and cleaning methods, inflow and
infiltration (I/I) identification and control, sewer rehabilitation and repair, regulations and emergency
response , laboratory procedures, and basic mathematics for operators.
1. What is the primary purpose of a wastewater collection system?
A) Treat wastewater before discharge
B) Disinfect effluent before discharge
C) Collect and transport wastewater to a treatment facility
D) Store drinking water for distribution
Answer: C
Rationale: The collection system's main function is to safely convey wastewater from homes,
businesses, and industries to a treatment plant, preventing environmental contamination .
, Page 2 of 118
2. Which of the following is the most common cause of sanitary sewer overflows (SSOs)?
A) Pump station electrical failure
B) Blockages due to grease, roots, and debris
C) Heavy rainfall only
D) Treatment plant bypass
Answer: B
Rationale: Grease, roots, and debris can obstruct pipes, causing backups and overflows in the system.
Regular cleaning and maintenance help prevent these blockages .
3. What type of pipe material is most resistant to root intrusion?
A) Clay pipe
B) PVC
C) Cast iron
D) Concrete pipe
Answer: B
, Page 3 of 118
Rationale: PVC pipes have smooth walls and tight joints, making it difficult for roots to penetrate
compared to older clay or concrete pipes with more joints .
4. What is the minimum slope recommended for a 4-inch diameter sewer pipe?
A) 1/16 inch per foot
B) 1/8 inch per foot
C) 1/4 inch per foot
D) 1/2 inch per foot
Answer: B
Rationale: Adequate slope (typically 1/8 inch per foot for 4-inch pipe) ensures gravity flow without
causing sedimentation from excessive velocity or blockage from insufficient flow .
5. What is the purpose of a manhole in a collection system?
A) To increase flow velocity
B) To store sewage during peak flows
, Page 4 of 118
C) To provide access for inspection, maintenance, and flow measurement
D) To treat wastewater before discharge
Answer: C
Rationale: Manholes allow operators to inspect the system, remove blockages, and measure flow
without excavating the pipe .
6. Which gas is most commonly monitored in confined spaces in wastewater systems due to its toxicity
and flammability?
A) Carbon dioxide
B) Methane
C) Hydrogen sulfide (H₂S)
D) Nitrogen
Answer: C
Rationale: H₂S is toxic and flammable, produced by anaerobic decomposition of sewage. Monitoring is
essential to prevent worker injury or death .
