,TCEQ Class C Water Operator License
Exam 2026/2027 | 100 Verified
Questions & Answers | Texas
Commission on Environmental Quality
Prep | 5 Core Domains | Instant
Download | rated 100% correct.
DOMAIN 1: REGULATIONS AND PUBLIC HEALTH
PROTECTION
1. What is the minimum score required to pass the TCEQ water operator
licensing exam?
A) 60%
B) 65%
C) 70%
D) 75%
Correct Answer: C (70%)
Rationale: The minimum passing score for TCEQ occupational licensing
exams is 70% . A 70% passing score means you should study for mastery,
not bare minimums .
Source: TCEQ Exam Facts; 30 TAC Chapter 290
,2. Which federal law is the primary legislation governing public drinking
water safety in the United States?
A) Clean Water Act (CWA)
B) Resource Conservation and Recovery Act (RCRA)
C) Safe Drinking Water Act (SDWA)
D) National Environmental Policy Act (NEPA)
Correct Answer: C (Safe Drinking Water Act [SDWA])
Rationale: The Safe Drinking Water Act (SDWA), enacted in 1974 and
amended in 1986 and 1996, is the primary federal law that protects public
drinking water supplies throughout the United States .
Source: SDWA; TCEQ Exam Blueprint
3. What does MCL stand for in water quality regulations?
A) Maximum Contaminant Limit
B) Maximum Contaminant Level
C) Minimum Chlorine Limit
D) Mandatory Compliance Level
Correct Answer: B (Maximum Contaminant Level)
Rationale: MCL stands for Maximum Contaminant Level, which is the highest
permissible level of a contaminant in drinking water delivered to users. MCLs
are enforceable standards set by the EPA .
Source: EPA Drinking Water Standards; SDWA
4. What is the MCLG for total coliforms in drinking water?
A) 1 CFU/100 mL
B) 5% positive samples per month
C) Zero
D) 0.5 CFU/100 mL
Correct Answer: C (Zero)
, Rationale: The Maximum Contaminant Level Goal (MCLG) for total coliforms
is zero because any coliform bacteria in drinking water may pose a health
risk and indicates possible contamination .
Source: EPA Total Coliform Rule; SDWA
5. A Tier 1 Public Notice for E. coli contamination must be issued within how
many hours?
A) 8 hours
B) 24 hours
C) 48 hours
D) 72 hours
Correct Answer: B (24 hours)
Rationale: Tier 1 (acute health risk) requires notice within 24 hours via radio,
TV, or hand delivery .
Source: 40 CFR Part 141; TCEQ Public Notice Rule
6. The maximum contaminant level (MCL) for Total Trihalomethanes (TTHMs)
is:
A) 40 µg/L
B) 60 µg/L
C) 80 µg/L
D) 100 µg/L
Correct Answer: C (80 µg/L)
Rationale: EPA/TCEQ MCL for TTHMs is 0.080 mg/L (80 µg/L) as a running
annual average .
Source: Stage 2 Disinfectants and Disinfection Byproducts Rule
Exam 2026/2027 | 100 Verified
Questions & Answers | Texas
Commission on Environmental Quality
Prep | 5 Core Domains | Instant
Download | rated 100% correct.
DOMAIN 1: REGULATIONS AND PUBLIC HEALTH
PROTECTION
1. What is the minimum score required to pass the TCEQ water operator
licensing exam?
A) 60%
B) 65%
C) 70%
D) 75%
Correct Answer: C (70%)
Rationale: The minimum passing score for TCEQ occupational licensing
exams is 70% . A 70% passing score means you should study for mastery,
not bare minimums .
Source: TCEQ Exam Facts; 30 TAC Chapter 290
,2. Which federal law is the primary legislation governing public drinking
water safety in the United States?
A) Clean Water Act (CWA)
B) Resource Conservation and Recovery Act (RCRA)
C) Safe Drinking Water Act (SDWA)
D) National Environmental Policy Act (NEPA)
Correct Answer: C (Safe Drinking Water Act [SDWA])
Rationale: The Safe Drinking Water Act (SDWA), enacted in 1974 and
amended in 1986 and 1996, is the primary federal law that protects public
drinking water supplies throughout the United States .
Source: SDWA; TCEQ Exam Blueprint
3. What does MCL stand for in water quality regulations?
A) Maximum Contaminant Limit
B) Maximum Contaminant Level
C) Minimum Chlorine Limit
D) Mandatory Compliance Level
Correct Answer: B (Maximum Contaminant Level)
Rationale: MCL stands for Maximum Contaminant Level, which is the highest
permissible level of a contaminant in drinking water delivered to users. MCLs
are enforceable standards set by the EPA .
Source: EPA Drinking Water Standards; SDWA
4. What is the MCLG for total coliforms in drinking water?
A) 1 CFU/100 mL
B) 5% positive samples per month
C) Zero
D) 0.5 CFU/100 mL
Correct Answer: C (Zero)
, Rationale: The Maximum Contaminant Level Goal (MCLG) for total coliforms
is zero because any coliform bacteria in drinking water may pose a health
risk and indicates possible contamination .
Source: EPA Total Coliform Rule; SDWA
5. A Tier 1 Public Notice for E. coli contamination must be issued within how
many hours?
A) 8 hours
B) 24 hours
C) 48 hours
D) 72 hours
Correct Answer: B (24 hours)
Rationale: Tier 1 (acute health risk) requires notice within 24 hours via radio,
TV, or hand delivery .
Source: 40 CFR Part 141; TCEQ Public Notice Rule
6. The maximum contaminant level (MCL) for Total Trihalomethanes (TTHMs)
is:
A) 40 µg/L
B) 60 µg/L
C) 80 µg/L
D) 100 µg/L
Correct Answer: C (80 µg/L)
Rationale: EPA/TCEQ MCL for TTHMs is 0.080 mg/L (80 µg/L) as a running
annual average .
Source: Stage 2 Disinfectants and Disinfection Byproducts Rule
