Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
WASTEWATER CLASS B TEXAS
QUESTIONS WITH CORRECT ANSWERS
Edition
Aligned with: Texas Commission on Environmental Quality (TCEQ) Class B Wastewater Treatment Facility
Operator Exam Content
Regulatory Reference: Title 30 Texas Administrative Code (30 TAC), 40 CFR Parts 403, 503, OSHA 29 CFR
1910 & 1926
Total Questions: 225 | Time Limit (Official Exam): 2 hours (CBT) | Format: Multiple Choice (A-D), One
Correct Answer per Question
Cognitive Distribution: 25% Recall | 50% Application | 25% Analysis (Scenario-based)
Question Style: 70% Scenario-based | 30% Direct Knowledge
Examination Contents
# Section Questions
1 Section 1: TCEQ Rules, Regulations, & Safety (Q1–Q30) 30
2 Section 2: Treatment Process Fundamentals – BOD, TSS, & Basic Concepts (Q31–Q60) 30
3 Section 3: Preliminary & Primary Treatment (Q61–Q90) 30
4 Section 4: Secondary Treatment – Activated Sludge, Trickling Filters, RBC, & Ponds (Q91–Q120)
30
5 Section 5: Disinfection, Advanced Treatment, & Laboratory Procedures (Q121–Q145) 25
6 Section 6: Sludge Handling, Dewatering, & Biosolids Management (Q146–Q170) 25
7 Section 7: Collection Systems, Lift Stations, & Infiltration/Inflow (Q171–Q195) 25
8 Section 8: Operations, Maintenance, & Equipment (Q196–Q210) 15
9 Section 9: Comprehensive Case Studies & Scenario-Based Questions (Q211–Q225) 15
TOTAL QUESTIONS 225
Examination Instructions
1. This practice examination contains 225 multiple-choice questions distributed across 9 sections covering TCEQ
Class B Wastewater Treatment Facility Operator exam content. Each question has exactly one correct answer
marked with *[CORRECT]*.
2. The correct answer is identified by letter (A, B, C, or D) and a brief rationale is provided explaining why the
answer is correct and why other options are incorrect, with references to TCEQ regulations (30 TAC), federal
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 1
,Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
rules (40 CFR), OSHA standards, and industry best practices.
3. The official TCEQ Class B exam is computer-based with a 2-hour time limit. Candidates are eligible for four test
attempts within a one-year approval period (initial test plus up to three retests).
4. Use this practice exam for self-assessment: attempt each question without looking at the answer, then verify
your response and read the rationale to reinforce understanding. Pay particular attention to regulatory timelines
(24-hour verbal notification, 5-day written report, 1-year new-hire licensing), reporting requirements, and safety
protocols.
5. Cognitive distribution: 25% recall (basic facts and definitions), 50% application (process calculations and
operational decisions), 25% analysis (scenario-based and regulatory interpretation).
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 2
,Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
Section 1: TCEQ Rules, Regulations, & Safety
30 Questions — Regulatory Compliance, Reporting, Confined Space, Hazardous Gases
Q1: A Class B wastewater operator at a 2.5 MGD activated sludge facility discovers an
unauthorized sanitary sewer overflow (SSO) discharging approximately 8,000 gallons of
untreated wastewater into a tributary of the Brazos River. Under 30 TAC Chapter 305 and TCEQ
reporting rules, what is the operator's FIRST required action?
A. Submit a written discharge report to TCEQ within 5 days
B. Notify the TCEQ regional office verbally within 24 hours *[CORRECT]*
C. Wait until the spill is contained, then notify TCEQ within 72 hours
D. Notify the EPA Region 6 office in Dallas within 12 hours
Correct Answer: B
Rationale: Under 30 TAC §305.125 and TCEQ rules, accidental discharges, bypasses, and SSOs require
verbal notification of the appropriate TCEQ regional office within 24 hours, followed by a written report within
5 days. Option A describes the second step (written report), not the first required action. Option C
understates the urgency and misstates the timeline. Option D is incorrect because state-permitted facilities
report to TCEQ (the state delegated authority), not directly to EPA.
Q2: A newly hired operator trainee begins work at a Category III wastewater treatment facility in
Texas. Under 30 TAC Chapter 30 licensing rules, what is the MAXIMUM time the trainee has to
obtain the appropriate operator license?
A. 6 months from date of hire
B. 1 year from date of hire *[CORRECT]*
C. 2 years from date of hire
D. Before being allowed to perform any operational duties
Correct Answer: B
Rationale: Per 30 TAC §30.301, newly hired operators at wastewater facilities have one year from their date
of hire to obtain the appropriate level of operator licensing. Option D is incorrect because trainees may
perform operational duties under the direct supervision of a licensed operator during this period. Option C (2
years) confuses the experience requirement for Class B licensure with the new-hire licensing deadline.
Q3: Which Texas state agency is the delegated authority responsible for administering the
NPDES/TPDES wastewater permitting program and enforcing pollution control laws in Texas?
A. Texas Department of State Health Services (DSHS)
B. U.S. Environmental Protection Agency Region 6 (EPA)
C. Texas Commission on Environmental Quality (TCEQ) *[CORRECT]*
D. Texas Water Development Board (TWDB)
Correct Answer: C
Rationale: TCEQ is the state agency delegated by EPA to administer the Texas Pollutant Discharge
Elimination System (TPDES) program under 30 TAC Chapter 305. EPA retains oversight but is not the
primary permitting authority in Texas. DSHS handles public health matters unrelated to wastewater
permitting. TWDB handles water planning and infrastructure financing, not regulatory enforcement.
Q4: Operations records and laboratory data at a Texas Class B wastewater facility must be
retained for a MINIMUM period of:
A. 1 year for all records
B. 3 years for operations/lab records; 5 years for sludge records *[CORRECT]*
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 3
, Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
C. 5 years for operations/lab records; 10 years for sludge records
D. 7 years for all records, matching IRS retention rules
Correct Answer: B
Rationale: 30 TAC and federal 40 CFR 503 require that operational and laboratory records be retained for a
minimum of 3 years, while sludge management records (including biosolids land application) must be
retained for 5 years. Option C inflates the requirement. Sludge/biosolids records are subject to the longer
retention period due to long-term liability and pathogen/trace pollutant tracking under 40 CFR Part 503.
Q5: A collection system crew is preparing to enter a 14-foot-deep manhole to clear a blockage.
Under OSHA 29 CFR 1910.146 and 1926 Subpart P, which combination of precautions is
REQUIRED before entry?
A. Ventilate the space, complete a confined space entry permit, test atmosphere, and provide a
standby attendant *[CORRECT]*
B. Open the manhole 15 minutes before entry to allow natural ventilation, then enter with a flashlight
C. Wear a half-mask respirator and safety harness; no permit required if the manhole is less than 20
feet deep
D. Notify TCEQ 24 hours in advance and obtain a written entry permit from the regional office
Correct Answer: A
Rationale: Manholes are permit-required confined spaces under OSHA 29 CFR 1910.146. Mandatory
precautions include atmospheric testing (O2, LEL, H2S, CO), ventilation, a completed entry permit,
continuous attendant outside the space, rescue equipment, and communication. Option B is
dangerous—natural ventilation alone is unreliable. Option C is incorrect because permit requirements are
based on space configuration and hazards, not depth alone. Option D misstates the regulatory authority:
OSHA governs entry, not TCEQ.
Q6: When using a ladder as a means of exit from an excavation, OSHA requires the ladder to:
A. Extend at least 1 foot above the ground and be placed within 50 feet laterally of any worker
B. Extend at least 3 feet above the ground and be secured within 25 feet laterally of any worker
in the excavation *[CORRECT]*
C. Extend at least 5 feet above the ground and be placed within 10 feet of the worker
D. Be rated for industrial use and placed at a 75-degree angle from horizontal
Correct Answer: B
Rationale: Per OSHA 29 CFR 1926.651(c)(2), ladders used as a means of egress from excavations must
extend at least 3 feet above the ground surface and be located within 25 feet of lateral travel distance of any
worker in the excavation. The ladder must also be secured against displacement. Options A, C, and D
misstate the dimensions or introduce requirements not in the standard.
Q7: An excavation for a sewer line repair is 7 feet deep in cohesive soil. Under OSHA 29 CFR
1926 Subpart P, the contractor MUST provide cave-in protection by:
A. Sloping, shoring, or using an approved trench box — required because depth exceeds 5 feet
*[CORRECT]*
B. Posting warning signs and a flagger; protective systems only required above 8 feet
C. Dewatering the excavation; sloping is only required for trenches deeper than 10 feet
D. Installing a fence; OSHA does not require shoring in cohesive soil
Correct Answer: A
Rationale: OSHA 29 CFR 1926.652 requires that all excavations greater than 5 feet in depth be protected by
sloping, shoring, or shielding (trench box), unless the excavation is made entirely in stable rock. Cohesive
soil alone is not an exemption. Option B is incorrect because 5 feet is the trigger, not 8. Option C confuses
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 4
WASTEWATER CLASS B TEXAS
QUESTIONS WITH CORRECT ANSWERS
Edition
Aligned with: Texas Commission on Environmental Quality (TCEQ) Class B Wastewater Treatment Facility
Operator Exam Content
Regulatory Reference: Title 30 Texas Administrative Code (30 TAC), 40 CFR Parts 403, 503, OSHA 29 CFR
1910 & 1926
Total Questions: 225 | Time Limit (Official Exam): 2 hours (CBT) | Format: Multiple Choice (A-D), One
Correct Answer per Question
Cognitive Distribution: 25% Recall | 50% Application | 25% Analysis (Scenario-based)
Question Style: 70% Scenario-based | 30% Direct Knowledge
Examination Contents
# Section Questions
1 Section 1: TCEQ Rules, Regulations, & Safety (Q1–Q30) 30
2 Section 2: Treatment Process Fundamentals – BOD, TSS, & Basic Concepts (Q31–Q60) 30
3 Section 3: Preliminary & Primary Treatment (Q61–Q90) 30
4 Section 4: Secondary Treatment – Activated Sludge, Trickling Filters, RBC, & Ponds (Q91–Q120)
30
5 Section 5: Disinfection, Advanced Treatment, & Laboratory Procedures (Q121–Q145) 25
6 Section 6: Sludge Handling, Dewatering, & Biosolids Management (Q146–Q170) 25
7 Section 7: Collection Systems, Lift Stations, & Infiltration/Inflow (Q171–Q195) 25
8 Section 8: Operations, Maintenance, & Equipment (Q196–Q210) 15
9 Section 9: Comprehensive Case Studies & Scenario-Based Questions (Q211–Q225) 15
TOTAL QUESTIONS 225
Examination Instructions
1. This practice examination contains 225 multiple-choice questions distributed across 9 sections covering TCEQ
Class B Wastewater Treatment Facility Operator exam content. Each question has exactly one correct answer
marked with *[CORRECT]*.
2. The correct answer is identified by letter (A, B, C, or D) and a brief rationale is provided explaining why the
answer is correct and why other options are incorrect, with references to TCEQ regulations (30 TAC), federal
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 1
,Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
rules (40 CFR), OSHA standards, and industry best practices.
3. The official TCEQ Class B exam is computer-based with a 2-hour time limit. Candidates are eligible for four test
attempts within a one-year approval period (initial test plus up to three retests).
4. Use this practice exam for self-assessment: attempt each question without looking at the answer, then verify
your response and read the rationale to reinforce understanding. Pay particular attention to regulatory timelines
(24-hour verbal notification, 5-day written report, 1-year new-hire licensing), reporting requirements, and safety
protocols.
5. Cognitive distribution: 25% recall (basic facts and definitions), 50% application (process calculations and
operational decisions), 25% analysis (scenario-based and regulatory interpretation).
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 2
,Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
Section 1: TCEQ Rules, Regulations, & Safety
30 Questions — Regulatory Compliance, Reporting, Confined Space, Hazardous Gases
Q1: A Class B wastewater operator at a 2.5 MGD activated sludge facility discovers an
unauthorized sanitary sewer overflow (SSO) discharging approximately 8,000 gallons of
untreated wastewater into a tributary of the Brazos River. Under 30 TAC Chapter 305 and TCEQ
reporting rules, what is the operator's FIRST required action?
A. Submit a written discharge report to TCEQ within 5 days
B. Notify the TCEQ regional office verbally within 24 hours *[CORRECT]*
C. Wait until the spill is contained, then notify TCEQ within 72 hours
D. Notify the EPA Region 6 office in Dallas within 12 hours
Correct Answer: B
Rationale: Under 30 TAC §305.125 and TCEQ rules, accidental discharges, bypasses, and SSOs require
verbal notification of the appropriate TCEQ regional office within 24 hours, followed by a written report within
5 days. Option A describes the second step (written report), not the first required action. Option C
understates the urgency and misstates the timeline. Option D is incorrect because state-permitted facilities
report to TCEQ (the state delegated authority), not directly to EPA.
Q2: A newly hired operator trainee begins work at a Category III wastewater treatment facility in
Texas. Under 30 TAC Chapter 30 licensing rules, what is the MAXIMUM time the trainee has to
obtain the appropriate operator license?
A. 6 months from date of hire
B. 1 year from date of hire *[CORRECT]*
C. 2 years from date of hire
D. Before being allowed to perform any operational duties
Correct Answer: B
Rationale: Per 30 TAC §30.301, newly hired operators at wastewater facilities have one year from their date
of hire to obtain the appropriate level of operator licensing. Option D is incorrect because trainees may
perform operational duties under the direct supervision of a licensed operator during this period. Option C (2
years) confuses the experience requirement for Class B licensure with the new-hire licensing deadline.
Q3: Which Texas state agency is the delegated authority responsible for administering the
NPDES/TPDES wastewater permitting program and enforcing pollution control laws in Texas?
A. Texas Department of State Health Services (DSHS)
B. U.S. Environmental Protection Agency Region 6 (EPA)
C. Texas Commission on Environmental Quality (TCEQ) *[CORRECT]*
D. Texas Water Development Board (TWDB)
Correct Answer: C
Rationale: TCEQ is the state agency delegated by EPA to administer the Texas Pollutant Discharge
Elimination System (TPDES) program under 30 TAC Chapter 305. EPA retains oversight but is not the
primary permitting authority in Texas. DSHS handles public health matters unrelated to wastewater
permitting. TWDB handles water planning and infrastructure financing, not regulatory enforcement.
Q4: Operations records and laboratory data at a Texas Class B wastewater facility must be
retained for a MINIMUM period of:
A. 1 year for all records
B. 3 years for operations/lab records; 5 years for sludge records *[CORRECT]*
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 3
, Wastewater Class B Texas — Practice Examination (2026/2027 Edition) TCEQ Class B Wastewater Operator Practice Exam
C. 5 years for operations/lab records; 10 years for sludge records
D. 7 years for all records, matching IRS retention rules
Correct Answer: B
Rationale: 30 TAC and federal 40 CFR 503 require that operational and laboratory records be retained for a
minimum of 3 years, while sludge management records (including biosolids land application) must be
retained for 5 years. Option C inflates the requirement. Sludge/biosolids records are subject to the longer
retention period due to long-term liability and pathogen/trace pollutant tracking under 40 CFR Part 503.
Q5: A collection system crew is preparing to enter a 14-foot-deep manhole to clear a blockage.
Under OSHA 29 CFR 1910.146 and 1926 Subpart P, which combination of precautions is
REQUIRED before entry?
A. Ventilate the space, complete a confined space entry permit, test atmosphere, and provide a
standby attendant *[CORRECT]*
B. Open the manhole 15 minutes before entry to allow natural ventilation, then enter with a flashlight
C. Wear a half-mask respirator and safety harness; no permit required if the manhole is less than 20
feet deep
D. Notify TCEQ 24 hours in advance and obtain a written entry permit from the regional office
Correct Answer: A
Rationale: Manholes are permit-required confined spaces under OSHA 29 CFR 1910.146. Mandatory
precautions include atmospheric testing (O2, LEL, H2S, CO), ventilation, a completed entry permit,
continuous attendant outside the space, rescue equipment, and communication. Option B is
dangerous—natural ventilation alone is unreliable. Option C is incorrect because permit requirements are
based on space configuration and hazards, not depth alone. Option D misstates the regulatory authority:
OSHA governs entry, not TCEQ.
Q6: When using a ladder as a means of exit from an excavation, OSHA requires the ladder to:
A. Extend at least 1 foot above the ground and be placed within 50 feet laterally of any worker
B. Extend at least 3 feet above the ground and be secured within 25 feet laterally of any worker
in the excavation *[CORRECT]*
C. Extend at least 5 feet above the ground and be placed within 10 feet of the worker
D. Be rated for industrial use and placed at a 75-degree angle from horizontal
Correct Answer: B
Rationale: Per OSHA 29 CFR 1926.651(c)(2), ladders used as a means of egress from excavations must
extend at least 3 feet above the ground surface and be located within 25 feet of lateral travel distance of any
worker in the excavation. The ladder must also be secured against displacement. Options A, C, and D
misstate the dimensions or introduce requirements not in the standard.
Q7: An excavation for a sewer line repair is 7 feet deep in cohesive soil. Under OSHA 29 CFR
1926 Subpart P, the contractor MUST provide cave-in protection by:
A. Sloping, shoring, or using an approved trench box — required because depth exceeds 5 feet
*[CORRECT]*
B. Posting warning signs and a flagger; protective systems only required above 8 feet
C. Dewatering the excavation; sloping is only required for trenches deeper than 10 feet
D. Installing a fence; OSHA does not require shoring in cohesive soil
Correct Answer: A
Rationale: OSHA 29 CFR 1926.652 requires that all excavations greater than 5 feet in depth be protected by
sloping, shoring, or shielding (trench box), unless the excavation is made entirely in stable rock. Cohesive
soil alone is not an exemption. Option B is incorrect because 5 feet is the trigger, not 8. Option C confuses
© 2026 Practice Examination — TCEQ Class B Wastewater Operator Preparation Page 4
