Page 1 of 149
TCEQ Class C Water License Exam QUESTIONS AND
VERIFIED SOLUTIONS WITH RATIONALES JUST RELEASED
TCEQ Class C Water License Exam - Complete Study Guide
10 POINT FORM EXAM COVERAGE AREAS (MOSTLY TESTED)
1. TCEQ Regulations and the Safe Drinking Water Act (SDWA) - The Texas Commission on Environmental
Quality (TCEQ) enforces the SDWA in Texas. Understanding MCLs, public notification requirements, and
Consumer Confidence Reports is essential.
2. Water Treatment Processes - Coagulation, flocculation, sedimentation, and filtration. Coagulation
neutralizes particle charges so they can clump; flocculation forms larger settleable particles; sedimentation
uses gravity settling; rapid sand filters use physical straining and adsorption.
3. Disinfection and Chlorination - Chlorine dosage, demand, and residual. Dosage = Demand + Residual.
Minimum free chlorine residual: 0.2 mg/L; minimum chloramine residual: 0.5 mg/L. Superchlorination for
new mains: 50 mg/L.
4. Distribution System Operations - Minimum operating pressure: 35 psi normal, 20 psi minimum. Elevated
storage tanks maintain pressure via gravity and require corrosion protection via painting and cathodic
protection.
5. Cross-Connection Control and Backflow Prevention - A physical air gap is the most effective backflow
prevention method. Backflow occurs via backsiphonage (negative pressure) or backpressure. Vacuum
breakers prevent backsiphonage at hose bibs.
6. Well Operations and Groundwater - Drawdown = static water level - pumping water level. An airline on a
well measures water levels. Aquifers are water-bearing underground formations.
7. Water Quality Parameters - pH scale: 0–14; neutral is 7. Water with pH 6.0 is acidic; pH 8.3 is basic.
Turbidity measures cloudiness from suspended particles.
8. Bacteriological Sampling and Coliform Rule - For systems collecting ≥40 samples/month: ≤5% positive for
total coliform. For systems <40 samples/month: no more than 1 positive. E. coli positive requires 3 repeat
samples within 24 hours and TCEQ notification.
9. Storage Tanks and Hydraulics - Standpipe pressure calculation: psi = feet × 0.433. Tank volume calculation
uses π × r² × height × 7.48 gallons/cubic foot.
10. Licensing and Certification - Class C requires 2 years of experience, with at least 1/2 in the specific field.
Licenses renew every 3 years with 30 hours of CE. Exam fee: $111.
1. What is the primary state agency responsible for enforcing the Safe Drinking Water Act (SDWA) in Texas?
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A. Texas Department of Health
B. Texas Commission on Environmental Quality (TCEQ)
C. Environmental Protection Agency (EPA)
D. Texas State Board of Fire Insurance
Answer: B - The TCEQ is the primary state agency responsible for enforcing the Safe Drinking Water Act in
Texas. The EPA sets federal standards, but TCEQ implements and enforces them at the state level.
---
2. Under TCEQ regulations, what is the minimum operating pressure that must be maintained in a water
distribution system under normal conditions?
A. 20 psi
B. 25 psi
C. 35 psi
D. 50 psi
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Answer: C - TCEQ rules require water systems to maintain a minimum of 35 psi throughout the distribution
system under normal operating conditions. The minimum in emergencies is 20 psi.
---
3. What is the minimum pressure that must be maintained in a water distribution system during
emergencies according to TCEQ regulations?
A. 10 psi
B. 20 psi
C. 35 psi
D. 50 psi
Answer: B - The minimum pressure during emergencies is 20 psi. This lower standard allows for temporary
pressure drops while maintaining some level of service.
---
4. When a water sample tests positive for E. coli in a public water system, what is the required action?
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A. Collect one repeat sample within 24 hours
B. Issue a boil water notice within 48 hours
C. Collect 3 repeat samples within 24 hours and notify TCEQ within 24 hours
D. Nothing, unless two consecutive positives occur
Answer: C - An E. coli positive requires immediate action: 3 repeat samples within 24 hours and TCEQ
notification within 24 hours. This is required under the Revised Total Coliform Rule.
---
5. What is the maximum contaminant level (MCL) for total trihalomethanes (TTHMs) in a community water
system?
A. 0.010 mg/L
B. 0.040 mg/L
C. 0.080 mg/L
D. 0.100 mg/L
Answer: C - The MCL for total trihalomethanes (TTHMs) is 0.080 mg/L. THMs are disinfection byproducts
formed when chlorine reacts with natural organic matter in water.
TCEQ Class C Water License Exam QUESTIONS AND
VERIFIED SOLUTIONS WITH RATIONALES JUST RELEASED
TCEQ Class C Water License Exam - Complete Study Guide
10 POINT FORM EXAM COVERAGE AREAS (MOSTLY TESTED)
1. TCEQ Regulations and the Safe Drinking Water Act (SDWA) - The Texas Commission on Environmental
Quality (TCEQ) enforces the SDWA in Texas. Understanding MCLs, public notification requirements, and
Consumer Confidence Reports is essential.
2. Water Treatment Processes - Coagulation, flocculation, sedimentation, and filtration. Coagulation
neutralizes particle charges so they can clump; flocculation forms larger settleable particles; sedimentation
uses gravity settling; rapid sand filters use physical straining and adsorption.
3. Disinfection and Chlorination - Chlorine dosage, demand, and residual. Dosage = Demand + Residual.
Minimum free chlorine residual: 0.2 mg/L; minimum chloramine residual: 0.5 mg/L. Superchlorination for
new mains: 50 mg/L.
4. Distribution System Operations - Minimum operating pressure: 35 psi normal, 20 psi minimum. Elevated
storage tanks maintain pressure via gravity and require corrosion protection via painting and cathodic
protection.
5. Cross-Connection Control and Backflow Prevention - A physical air gap is the most effective backflow
prevention method. Backflow occurs via backsiphonage (negative pressure) or backpressure. Vacuum
breakers prevent backsiphonage at hose bibs.
6. Well Operations and Groundwater - Drawdown = static water level - pumping water level. An airline on a
well measures water levels. Aquifers are water-bearing underground formations.
7. Water Quality Parameters - pH scale: 0–14; neutral is 7. Water with pH 6.0 is acidic; pH 8.3 is basic.
Turbidity measures cloudiness from suspended particles.
8. Bacteriological Sampling and Coliform Rule - For systems collecting ≥40 samples/month: ≤5% positive for
total coliform. For systems <40 samples/month: no more than 1 positive. E. coli positive requires 3 repeat
samples within 24 hours and TCEQ notification.
9. Storage Tanks and Hydraulics - Standpipe pressure calculation: psi = feet × 0.433. Tank volume calculation
uses π × r² × height × 7.48 gallons/cubic foot.
10. Licensing and Certification - Class C requires 2 years of experience, with at least 1/2 in the specific field.
Licenses renew every 3 years with 30 hours of CE. Exam fee: $111.
1. What is the primary state agency responsible for enforcing the Safe Drinking Water Act (SDWA) in Texas?
, Page 2 of 149
A. Texas Department of Health
B. Texas Commission on Environmental Quality (TCEQ)
C. Environmental Protection Agency (EPA)
D. Texas State Board of Fire Insurance
Answer: B - The TCEQ is the primary state agency responsible for enforcing the Safe Drinking Water Act in
Texas. The EPA sets federal standards, but TCEQ implements and enforces them at the state level.
---
2. Under TCEQ regulations, what is the minimum operating pressure that must be maintained in a water
distribution system under normal conditions?
A. 20 psi
B. 25 psi
C. 35 psi
D. 50 psi
, Page 3 of 149
Answer: C - TCEQ rules require water systems to maintain a minimum of 35 psi throughout the distribution
system under normal operating conditions. The minimum in emergencies is 20 psi.
---
3. What is the minimum pressure that must be maintained in a water distribution system during
emergencies according to TCEQ regulations?
A. 10 psi
B. 20 psi
C. 35 psi
D. 50 psi
Answer: B - The minimum pressure during emergencies is 20 psi. This lower standard allows for temporary
pressure drops while maintaining some level of service.
---
4. When a water sample tests positive for E. coli in a public water system, what is the required action?
, Page 4 of 149
A. Collect one repeat sample within 24 hours
B. Issue a boil water notice within 48 hours
C. Collect 3 repeat samples within 24 hours and notify TCEQ within 24 hours
D. Nothing, unless two consecutive positives occur
Answer: C - An E. coli positive requires immediate action: 3 repeat samples within 24 hours and TCEQ
notification within 24 hours. This is required under the Revised Total Coliform Rule.
---
5. What is the maximum contaminant level (MCL) for total trihalomethanes (TTHMs) in a community water
system?
A. 0.010 mg/L
B. 0.040 mg/L
C. 0.080 mg/L
D. 0.100 mg/L
Answer: C - The MCL for total trihalomethanes (TTHMs) is 0.080 mg/L. THMs are disinfection byproducts
formed when chlorine reacts with natural organic matter in water.
