Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
TEXAS WASTEWATER B EXAM QUESTIONS
WITH CORRECT ANSWERS 2026/2027
Comprehensive Certification Examination — 150 Questions
Aligned with TCEQ Wastewater Operator Licensing Standards, 30 TAC Chapter 30 Regulations, and Water Environment
Federation (WEF) Wastewater Operator Competencies (2026/2027 Edition)
EXAMINATION INSTRUCTIONS: This examination consists of 150 multiple-choice questions divided
across nine (9) content sections. Each question has four (4) options labeled A through D with exactly ONE
correct answer. The correct answer is marked *[CORRECT]* and followed by a rationale citing the applicable
TCEQ regulation, 30 TAC Chapter 30 provision, or standard wastewater treatment reference. Cognitive
distribution: 25% recall, 50% application, 25% analysis. Question style: 75% scenario-based (operational
situations, process control decisions, regulatory compliance) and 25% direct knowledge. Special inclusions: 20
scenario-based operational questions, 15 calculation-based questions, and 15 Texas-specific regulation
questions.
Section 1: Regulations, General Knowledge, & Safety (Q1–Q20)
Q1: Under the Texas Water Code Chapter 26, the Texas Commission on Environmental Quality (TCEQ)
has primary authority over wastewater discharges. A Class B operator discovers an unauthorized
discharge of untreated wastewater into a nearby creek. According to 30 TAC Chapter 30, what is the
maximum time allowed for notifying TCEQ?
A. 48 hours after discovery
B. 24 hours after discovery *[CORRECT]*
C. 72 hours after discovery
D. 12 hours after discovery
Correct Answer: B
Rationale: Under 30 TAC Section 30.15 and Texas Water Code §26.039, any unauthorized discharge of wastewater must
be reported to TCEQ within 24 hours of discovery. Option A (48 hours) and C (72 hours) exceed the regulatory window and
would constitute a separate violation. Option D (12 hours), while diligent, is not the statutory maximum. The 24-hour rule
ensures timely agency response to protect state waters and public health under TCEQ enforcement authority.
Q2: A wastewater operator in Texas holds a valid Class B license. According to 30 TAC Chapter 30, what
is the minimum number of continuing education hours required during the 3-year renewal cycle to
maintain an active Class B wastewater operator license?
A. 20 hours every 3 years
B. 30 hours every 3 years *[CORRECT]*
C. 40 hours every 3 years
D. 15 hours every 2 years
Correct Answer: B
Rationale: 30 TAC §30.208 requires Class B wastewater operators to complete 30 hours of TCEQ-approved continuing
education during each 3-year renewal cycle. Option A (20 hours) applies to Class D licenses. Option C (40 hours) exceeds
the Class B requirement and is more typical of Class A. Option D reflects an incorrect cycle length. Failure to complete
continuing education results in license expiration and prohibits the operator from legally operating the facility.
Texas Wastewater B Exam — 150 Questions Page 1
,Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Q3: Which of the following correctly describes the wastewater operator licensing class hierarchy in Texas,
from lowest to highest level of certification?
A. Class A → Class B → Class C → Class D
B. Class D → Class C → Class B → Class A *[CORRECT]*
C. Class C → Class D → Class A → Class B
D. Class B → Class D → Class C → Class A
Correct Answer: B
Rationale: Under 30 TAC §30.30, Texas wastewater operator licenses progress from Class D (entry level) → Class C →
Class B → Class A (highest). Each class requires progressively more experience, education, and examination. Class D
operators may work under supervision; Class A operators can manage the largest and most complex facilities. The
progression in Option B is the only correct ascending order. Other options scramble the hierarchy and would misrepresent
licensing eligibility.
Q4: A facility operator is preparing to dispose of biosolids by land application on agricultural sites. Which
federal regulation establishes the standards for biosolids use and disposal, including pollutant limits,
pathogen reduction requirements, and management practices?
A. 40 CFR Part 403 (Pretreatment)
B. 40 CFR Part 503 (Standards for the Use or Disposal of Sewage Sludge) *[CORRECT]*
C. 40 CFR Part 122 (NPDES Permits)
D. 40 CFR Part 136 (Test Procedures)
Correct Answer: B
Rationale: 40 CFR Part 503 establishes the comprehensive federal framework for biosolids use and disposal, including
ceiling concentrations for heavy metals (pollutant limits), Class A and Class B pathogen reduction alternatives, vector
attraction reduction requirements, and management practices. Option A addresses industrial pretreatment. Option C governs
NPDES permit issuance. Option D specifies approved analytical methods. Part 503 is implemented in Texas through TCEQ
authorization.
Q5: A Class B operator is reviewing documentation retention requirements for the wastewater treatment
facility. According to 30 TAC Chapter 30 and federal regulations, what is the minimum retention period
for sludge management records (including biosolids land application logs)?
A. 3 years
B. 5 years *[CORRECT]*
C. 7 years
D. 10 years
Correct Answer: B
Rationale: 40 CFR §503.17 requires sludge management records to be retained for a minimum of 5 years, with certain
pollutant concentration records retained indefinitely if the facility exceeds cumulative pollutant loading limits. Operational
records under 30 TAC are generally retained for 3 years (Option A), but sludge/biosolids records carry the longer 5-year
federal retention requirement. Options C and D exceed the regulatory minimum and would unnecessarily burden the
facility.
Q6: An operator must enter a confined space (a 12-foot-deep wet well) to clear a blockage. According to
OSHA 29 CFR 1910.146 and standard wastewater safety practices, which of the following is the FIRST
required action before entry?
A. Don a self-contained breathing apparatus (SCBA)
B. Verify atmospheric testing for oxygen, LEL, and toxic gases *[CORRECT]*
C. Establish communication with the standby attendant
D. Set up retrieval tripod and lifeline
Correct Answer: B
Texas Wastewater B Exam — 150 Questions Page 2
,Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Rationale: OSHA 29 CFR 1910.146 mandates atmospheric testing as the first action before any permit-required confined
space entry. The atmosphere must be tested for oxygen concentration (19.5–23.5%), combustible gases (LEL < 10%), and
toxic substances (H2S, CO) in that order. Options A, C, and D are essential safety measures but must follow atmospheric
verification. Entering without testing is a leading cause of wastewater worker fatalities and would violate OSHA, TCEQ,
and facility safety protocols.
Q7: A facility operates under a Texas Pollutant Discharge Elimination System (TPDES) permit that
specifies a monthly average effluent BOD5 limit of 20 mg/L and a weekly average limit of 30 mg/L.
During one week, the operator records daily BOD5 values averaging 32 mg/L. What is the correct
regulatory consequence and required action?
A. No action needed; the monthly average is still below 20 mg/L
B. The weekly average limit has been exceeded; the violation must be reported on the DMR and
investigated *[CORRECT]*
C. Increase chlorination dose immediately
D. Switch to extended aeration mode
Correct Answer: B
Rationale: TPDES permits under 30 TAC Chapter 309 contain both monthly and weekly average limits; exceeding either
constitutes a permit violation. The operator must record the exceedance on the Discharge Monitoring Report (DMR), initiate
a corrective action investigation, and document the root cause. Option A is incorrect because weekly limits are independently
enforceable. Options C and D are operational responses but do not satisfy the mandatory reporting requirement under
TPDES compliance provisions.
Q8: The Clean Water Act (CWA) is the foundational federal statute governing water pollution control in
the United States. Which specific section of the CWA establishes the National Pollutant Discharge
Elimination System (NPDES) permit program that Texas administers through TCEQ as TPDES?
A. Section 303 (Water Quality Standards)
B. Section 402 (NPDES Permit Program) *[CORRECT]*
C. Section 404 (Dredge and Fill Permits)
D. Section 311 (Oil and Hazardous Substance Liability)
Correct Answer: B
Rationale: Section 402 of the Clean Water Act (33 U.S.C. §1342) established the NPDES permit program, which authorizes
states to issue permits for point-source discharges to waters of the United States. Texas received NPDES delegation in 1998
and administers the program as TPDES under 30 TAC Chapter 305. Section 303 addresses water quality standards, Section
404 covers dredge/fill activities, and Section 311 addresses oil spills — none of which govern routine wastewater discharge
permitting.
Q9: A Class B operator is asked to sign a Discharge Monitoring Report (DMR). Under 40 CFR §122.22
and TPDES rules, which of the following statements about DMR certification is correct?
A. Any operator on staff may sign the DMR
B. The DMR must be signed by a principal executive officer, ranking elected official, or duly authorized
representative *[CORRECT]*
C. A maintenance technician may sign if the operator is unavailable
D. DMR signatures are optional for facilities with electronic reporting
Correct Answer: B
Rationale: 40 CFR §122.22 and 30 TAC §305.128 specify that DMRs and other TPDES reports must be signed by a
principal executive officer, ranking elected official, or a duly authorized representative (typically a certified operator of
appropriate class for the facility). Options A and C incorrectly suggest any staff member may sign. Option D is false —
electronic reporting still requires certification. False certification carries civil and criminal liability under the CWA.
Texas Wastewater B Exam — 150 Questions Page 3
, Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Q10: During a routine inspection, a TCEQ investigator asks the operator to produce the facility's Spill
Prevention Control and Countermeasure (SPCC) plan, chlorine handling procedures, and confined space
entry program. Which regulation primarily governs the chlorine safety program for wastewater facilities
using chlorine gas?
A. OSHA 29 CFR 1910.119 (Process Safety Management of Highly Hazardous Chemicals)
*[CORRECT]*
B. 40 CFR Part 503
C. 30 TAC Chapter 217 (Design Criteria for Domestic Wastewater Systems)
D. 10 CFR Part 71
Correct Answer: A
Rationale: OSHA 29 CFR 1910.119 (Process Safety Management, or PSM) applies to facilities with chlorine gas quantities
at or above the threshold of 1,500 pounds (one ton container). Wastewater plants exceeding this inventory must maintain a
PSM program including process hazard analysis, operating procedures, training, and emergency planning. Option B governs
biosolids. Option C governs design criteria. Option D addresses radioactive materials transport. PSM is the primary federal
chlorine safety authority.
Q11: A wastewater operator is preparing to perform maintenance on a centrifugal pump. The
Lockout/Tagout (LOTO) procedure under 29 CFR 1910.147 requires a specific sequence of actions.
Which of the following represents the correct order?
A. Notify affected employees → Shut down equipment → Isolate energy sources → Apply locks and tags →
Dissipate stored energy → Verify isolation *[CORRECT]*
B. Apply locks and tags → Shut down equipment → Notify affected employees → Isolate energy sources → Verify
isolation → Dissipate stored energy
C. Isolate energy sources → Notify affected employees → Apply locks and tags → Shut down equipment →
Dissipate stored energy → Verify isolation
D. Shut down equipment → Dissipate stored energy → Isolate energy sources → Apply locks and tags → Notify
affected employees → Verify isolation
Correct Answer: A
Rationale: 29 CFR 1910.147 prescribes the LOTO sequence as: (1) notify affected employees, (2) shut down equipment
using normal procedures, (3) isolate energy sources, (4) apply locks and tags, (5) dissipate or restrain stored energy
(capacitors, springs, pressure), and (6) verify isolation by attempting start-up. Option A is the only correct sequence.
Reversing isolation and lock application (Option B) creates an electrocution hazard. Failure to verify isolation last (Option
D) may result in unexpected energization during maintenance.
Q12: A collection system crew is preparing to enter an excavated trench 7 feet deep to repair a broken
sewer lateral. According to OSHA 29 CFR 1926 Subpart P (Excavations), which of the following
protective systems is REQUIRED before crew entry?
A. No protection needed if soil appears stable
B. A trench box, shoring, sloping, or benching system must be in place *[CORRECT]*
C. A reflective safety vest and hard hat are sufficient
D. A spotter at the surface only
Correct Answer: B
Rationale: OSHA 29 CFR 1926.652 requires that all excavations deeper than 5 feet have a protective system (sloping,
benching, shoring, or shielding via trench box) in place before worker entry. At 7 feet deep, this trench clearly exceeds the
5-foot threshold. Option A is unsafe and illegal regardless of apparent soil stability. Options C and D do not address cave-in
hazards, which are the leading cause of trench fatalities. Soil classification determines the required sloping angle but not
whether protection is needed.
Texas Wastewater B Exam — 150 Questions Page 4
TEXAS WASTEWATER B EXAM QUESTIONS
WITH CORRECT ANSWERS 2026/2027
Comprehensive Certification Examination — 150 Questions
Aligned with TCEQ Wastewater Operator Licensing Standards, 30 TAC Chapter 30 Regulations, and Water Environment
Federation (WEF) Wastewater Operator Competencies (2026/2027 Edition)
EXAMINATION INSTRUCTIONS: This examination consists of 150 multiple-choice questions divided
across nine (9) content sections. Each question has four (4) options labeled A through D with exactly ONE
correct answer. The correct answer is marked *[CORRECT]* and followed by a rationale citing the applicable
TCEQ regulation, 30 TAC Chapter 30 provision, or standard wastewater treatment reference. Cognitive
distribution: 25% recall, 50% application, 25% analysis. Question style: 75% scenario-based (operational
situations, process control decisions, regulatory compliance) and 25% direct knowledge. Special inclusions: 20
scenario-based operational questions, 15 calculation-based questions, and 15 Texas-specific regulation
questions.
Section 1: Regulations, General Knowledge, & Safety (Q1–Q20)
Q1: Under the Texas Water Code Chapter 26, the Texas Commission on Environmental Quality (TCEQ)
has primary authority over wastewater discharges. A Class B operator discovers an unauthorized
discharge of untreated wastewater into a nearby creek. According to 30 TAC Chapter 30, what is the
maximum time allowed for notifying TCEQ?
A. 48 hours after discovery
B. 24 hours after discovery *[CORRECT]*
C. 72 hours after discovery
D. 12 hours after discovery
Correct Answer: B
Rationale: Under 30 TAC Section 30.15 and Texas Water Code §26.039, any unauthorized discharge of wastewater must
be reported to TCEQ within 24 hours of discovery. Option A (48 hours) and C (72 hours) exceed the regulatory window and
would constitute a separate violation. Option D (12 hours), while diligent, is not the statutory maximum. The 24-hour rule
ensures timely agency response to protect state waters and public health under TCEQ enforcement authority.
Q2: A wastewater operator in Texas holds a valid Class B license. According to 30 TAC Chapter 30, what
is the minimum number of continuing education hours required during the 3-year renewal cycle to
maintain an active Class B wastewater operator license?
A. 20 hours every 3 years
B. 30 hours every 3 years *[CORRECT]*
C. 40 hours every 3 years
D. 15 hours every 2 years
Correct Answer: B
Rationale: 30 TAC §30.208 requires Class B wastewater operators to complete 30 hours of TCEQ-approved continuing
education during each 3-year renewal cycle. Option A (20 hours) applies to Class D licenses. Option C (40 hours) exceeds
the Class B requirement and is more typical of Class A. Option D reflects an incorrect cycle length. Failure to complete
continuing education results in license expiration and prohibits the operator from legally operating the facility.
Texas Wastewater B Exam — 150 Questions Page 1
,Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Q3: Which of the following correctly describes the wastewater operator licensing class hierarchy in Texas,
from lowest to highest level of certification?
A. Class A → Class B → Class C → Class D
B. Class D → Class C → Class B → Class A *[CORRECT]*
C. Class C → Class D → Class A → Class B
D. Class B → Class D → Class C → Class A
Correct Answer: B
Rationale: Under 30 TAC §30.30, Texas wastewater operator licenses progress from Class D (entry level) → Class C →
Class B → Class A (highest). Each class requires progressively more experience, education, and examination. Class D
operators may work under supervision; Class A operators can manage the largest and most complex facilities. The
progression in Option B is the only correct ascending order. Other options scramble the hierarchy and would misrepresent
licensing eligibility.
Q4: A facility operator is preparing to dispose of biosolids by land application on agricultural sites. Which
federal regulation establishes the standards for biosolids use and disposal, including pollutant limits,
pathogen reduction requirements, and management practices?
A. 40 CFR Part 403 (Pretreatment)
B. 40 CFR Part 503 (Standards for the Use or Disposal of Sewage Sludge) *[CORRECT]*
C. 40 CFR Part 122 (NPDES Permits)
D. 40 CFR Part 136 (Test Procedures)
Correct Answer: B
Rationale: 40 CFR Part 503 establishes the comprehensive federal framework for biosolids use and disposal, including
ceiling concentrations for heavy metals (pollutant limits), Class A and Class B pathogen reduction alternatives, vector
attraction reduction requirements, and management practices. Option A addresses industrial pretreatment. Option C governs
NPDES permit issuance. Option D specifies approved analytical methods. Part 503 is implemented in Texas through TCEQ
authorization.
Q5: A Class B operator is reviewing documentation retention requirements for the wastewater treatment
facility. According to 30 TAC Chapter 30 and federal regulations, what is the minimum retention period
for sludge management records (including biosolids land application logs)?
A. 3 years
B. 5 years *[CORRECT]*
C. 7 years
D. 10 years
Correct Answer: B
Rationale: 40 CFR §503.17 requires sludge management records to be retained for a minimum of 5 years, with certain
pollutant concentration records retained indefinitely if the facility exceeds cumulative pollutant loading limits. Operational
records under 30 TAC are generally retained for 3 years (Option A), but sludge/biosolids records carry the longer 5-year
federal retention requirement. Options C and D exceed the regulatory minimum and would unnecessarily burden the
facility.
Q6: An operator must enter a confined space (a 12-foot-deep wet well) to clear a blockage. According to
OSHA 29 CFR 1910.146 and standard wastewater safety practices, which of the following is the FIRST
required action before entry?
A. Don a self-contained breathing apparatus (SCBA)
B. Verify atmospheric testing for oxygen, LEL, and toxic gases *[CORRECT]*
C. Establish communication with the standby attendant
D. Set up retrieval tripod and lifeline
Correct Answer: B
Texas Wastewater B Exam — 150 Questions Page 2
,Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Rationale: OSHA 29 CFR 1910.146 mandates atmospheric testing as the first action before any permit-required confined
space entry. The atmosphere must be tested for oxygen concentration (19.5–23.5%), combustible gases (LEL < 10%), and
toxic substances (H2S, CO) in that order. Options A, C, and D are essential safety measures but must follow atmospheric
verification. Entering without testing is a leading cause of wastewater worker fatalities and would violate OSHA, TCEQ,
and facility safety protocols.
Q7: A facility operates under a Texas Pollutant Discharge Elimination System (TPDES) permit that
specifies a monthly average effluent BOD5 limit of 20 mg/L and a weekly average limit of 30 mg/L.
During one week, the operator records daily BOD5 values averaging 32 mg/L. What is the correct
regulatory consequence and required action?
A. No action needed; the monthly average is still below 20 mg/L
B. The weekly average limit has been exceeded; the violation must be reported on the DMR and
investigated *[CORRECT]*
C. Increase chlorination dose immediately
D. Switch to extended aeration mode
Correct Answer: B
Rationale: TPDES permits under 30 TAC Chapter 309 contain both monthly and weekly average limits; exceeding either
constitutes a permit violation. The operator must record the exceedance on the Discharge Monitoring Report (DMR), initiate
a corrective action investigation, and document the root cause. Option A is incorrect because weekly limits are independently
enforceable. Options C and D are operational responses but do not satisfy the mandatory reporting requirement under
TPDES compliance provisions.
Q8: The Clean Water Act (CWA) is the foundational federal statute governing water pollution control in
the United States. Which specific section of the CWA establishes the National Pollutant Discharge
Elimination System (NPDES) permit program that Texas administers through TCEQ as TPDES?
A. Section 303 (Water Quality Standards)
B. Section 402 (NPDES Permit Program) *[CORRECT]*
C. Section 404 (Dredge and Fill Permits)
D. Section 311 (Oil and Hazardous Substance Liability)
Correct Answer: B
Rationale: Section 402 of the Clean Water Act (33 U.S.C. §1342) established the NPDES permit program, which authorizes
states to issue permits for point-source discharges to waters of the United States. Texas received NPDES delegation in 1998
and administers the program as TPDES under 30 TAC Chapter 305. Section 303 addresses water quality standards, Section
404 covers dredge/fill activities, and Section 311 addresses oil spills — none of which govern routine wastewater discharge
permitting.
Q9: A Class B operator is asked to sign a Discharge Monitoring Report (DMR). Under 40 CFR §122.22
and TPDES rules, which of the following statements about DMR certification is correct?
A. Any operator on staff may sign the DMR
B. The DMR must be signed by a principal executive officer, ranking elected official, or duly authorized
representative *[CORRECT]*
C. A maintenance technician may sign if the operator is unavailable
D. DMR signatures are optional for facilities with electronic reporting
Correct Answer: B
Rationale: 40 CFR §122.22 and 30 TAC §305.128 specify that DMRs and other TPDES reports must be signed by a
principal executive officer, ranking elected official, or a duly authorized representative (typically a certified operator of
appropriate class for the facility). Options A and C incorrectly suggest any staff member may sign. Option D is false —
electronic reporting still requires certification. False certification carries civil and criminal liability under the CWA.
Texas Wastewater B Exam — 150 Questions Page 3
, Texas Wastewater B Operator Certification Exam 2026/2027 TCEQ | 30 TAC Chapter 30 | WEF Competencies
Q10: During a routine inspection, a TCEQ investigator asks the operator to produce the facility's Spill
Prevention Control and Countermeasure (SPCC) plan, chlorine handling procedures, and confined space
entry program. Which regulation primarily governs the chlorine safety program for wastewater facilities
using chlorine gas?
A. OSHA 29 CFR 1910.119 (Process Safety Management of Highly Hazardous Chemicals)
*[CORRECT]*
B. 40 CFR Part 503
C. 30 TAC Chapter 217 (Design Criteria for Domestic Wastewater Systems)
D. 10 CFR Part 71
Correct Answer: A
Rationale: OSHA 29 CFR 1910.119 (Process Safety Management, or PSM) applies to facilities with chlorine gas quantities
at or above the threshold of 1,500 pounds (one ton container). Wastewater plants exceeding this inventory must maintain a
PSM program including process hazard analysis, operating procedures, training, and emergency planning. Option B governs
biosolids. Option C governs design criteria. Option D addresses radioactive materials transport. PSM is the primary federal
chlorine safety authority.
Q11: A wastewater operator is preparing to perform maintenance on a centrifugal pump. The
Lockout/Tagout (LOTO) procedure under 29 CFR 1910.147 requires a specific sequence of actions.
Which of the following represents the correct order?
A. Notify affected employees → Shut down equipment → Isolate energy sources → Apply locks and tags →
Dissipate stored energy → Verify isolation *[CORRECT]*
B. Apply locks and tags → Shut down equipment → Notify affected employees → Isolate energy sources → Verify
isolation → Dissipate stored energy
C. Isolate energy sources → Notify affected employees → Apply locks and tags → Shut down equipment →
Dissipate stored energy → Verify isolation
D. Shut down equipment → Dissipate stored energy → Isolate energy sources → Apply locks and tags → Notify
affected employees → Verify isolation
Correct Answer: A
Rationale: 29 CFR 1910.147 prescribes the LOTO sequence as: (1) notify affected employees, (2) shut down equipment
using normal procedures, (3) isolate energy sources, (4) apply locks and tags, (5) dissipate or restrain stored energy
(capacitors, springs, pressure), and (6) verify isolation by attempting start-up. Option A is the only correct sequence.
Reversing isolation and lock application (Option B) creates an electrocution hazard. Failure to verify isolation last (Option
D) may result in unexpected energization during maintenance.
Q12: A collection system crew is preparing to enter an excavated trench 7 feet deep to repair a broken
sewer lateral. According to OSHA 29 CFR 1926 Subpart P (Excavations), which of the following
protective systems is REQUIRED before crew entry?
A. No protection needed if soil appears stable
B. A trench box, shoring, sloping, or benching system must be in place *[CORRECT]*
C. A reflective safety vest and hard hat are sufficient
D. A spotter at the surface only
Correct Answer: B
Rationale: OSHA 29 CFR 1926.652 requires that all excavations deeper than 5 feet have a protective system (sloping,
benching, shoring, or shielding via trench box) in place before worker entry. At 7 feet deep, this trench clearly exceeds the
5-foot threshold. Option A is unsafe and illegal regardless of apparent soil stability. Options C and D do not address cave-in
hazards, which are the leading cause of trench fatalities. Soil classification determines the required sloping angle but not
whether protection is needed.
Texas Wastewater B Exam — 150 Questions Page 4
