Complete 2025/2026 Texas
Wastewater Class I
Operator Exam Study Guide
– Expert-Verified Questions
and Answers with In-Depth
Explanations
Introduction
This study guide is designed for operators preparing for the Texas Commission on
Environmental Quality (TCEQ) Class I Wastewater Operator Certification Exam for the
2025/2026 cycle. It focuses on key topics including wastewater collection, treatment
processes, safety, regulations, and operational practices. The guide contains over 100
practice questions, each with a clear answer and an in-depth explanation to build
understanding. Questions are drawn from reliable sources and verified for accuracy. Use
this to test knowledge, identify weak areas, and reinforce concepts essential for passing
the exam and excelling in the field.
Section 1: Wastewater Fundamentals and Regulations
(Questions 1-20)
1. Question: What is the primary objective of the Clean Water Act of 1972?
Answer: Restore and maintain the chemical, physical, and biological integrity of
water in the US.
, Explanation: The Clean Water Act sets goals to protect water bodies from pollution
by regulating discharges and ensuring safe water for fishing and swimming. In
Texas, this supports TCEQ permits that limit pollutants like BOD and TSS in effluent,
helping operators maintain compliance and prevent environmental harm from
untreated wastewater.
2. Question: What does NPDES stand for?
Answer: National Pollutant Discharge Elimination System.
Explanation: NPDES is the federal program under the EPA that controls point source
pollution into US waters. In Texas, TCEQ administers it for wastewater plants, requiring
operators to monitor and report discharges to avoid fines and ensure effluent meets limits,
such as no more than 30 mg/L BOD5.
3. Question: Chapter _____ of the Texas Water Code is the state law controlling water
pollution and _____ authority to control discharges in Texas.
Answer: Chapter 26; TCEQ.
Explanation: Chapter 26 empowers TCEQ to issue permits, set standards, and enforce
rules for wastewater treatment. Operators must follow these to operate legally, including
daily monitoring of flows and residuals, which prevents illegal discharges and protects
public health from pathogens.
4. Question: The name of the State Agency responsible for enforcing pollution control
laws in Texas is?
Answer: Texas Commission on Environmental Quality (TCEQ).
Explanation: TCEQ oversees licensing, inspections, and compliance for wastewater
systems. Class I operators report to TCEQ on plant performance, ensuring treatment
removes 85-95% of pollutants before discharge, which safeguards rivers and groundwater
from contamination.
5. Question: A licensed wastewater operator is a professional who?
Answer: Protects public health, operates treatment systems safely, and complies with
regulations.
, Explanation: Operators manage collection and treatment to remove solids, organics, and
pathogens. This role involves daily checks on pumps, clarifiers, and disinfection, reducing
disease risks like cholera and maintaining Texas stream standards for dissolved oxygen
above 5 mg/L.
6. Question: What is TCEQ doing to control "point source" pollution of the Texas
waterways?
Answer: Permitting of domestic and industrial wastewater plants.
Explanation: Point sources are direct discharges from pipes. TCEQ issues Texas Pollutant
Discharge Elimination System (TPDES) permits with limits on parameters like pH (6-9) and
chlorine residual (1 mg/L), allowing operators to adjust processes for consistent effluent
quality.
7. Question: The term pathogenic means?
Answer: Capable of causing disease.
Explanation: Pathogens in wastewater include bacteria and viruses that spread illness.
Treatment like chlorination kills 99.99% of them, with operators verifying via fecal coliform
tests (under 200/100mL), preventing outbreaks in communities relying on treated water
reuse.
8. Question: The minimum separation between sewer lines and potable water lines
is?
Answer: 9 feet.
Explanation: This vertical separation prevents cross-contamination from leaks. In Texas,
it's a TCEQ rule to avoid groundwater pollution; operators inspect lines regularly to ensure
no breaches, protecting drinking water supplies from sewage intrusion.
9. Question: An important step in testing a sample for Total Suspended Solids (TSS)
is?
Answer: Filtering the sample.
Explanation: TSS measures particles caught on a filter after drying at 103°C. It's key for
efficiency (aim for <30 mg/L effluent); high TSS indicates poor settling, prompting operators
to adjust sludge wasting for clearer discharge.
Wastewater Class I
Operator Exam Study Guide
– Expert-Verified Questions
and Answers with In-Depth
Explanations
Introduction
This study guide is designed for operators preparing for the Texas Commission on
Environmental Quality (TCEQ) Class I Wastewater Operator Certification Exam for the
2025/2026 cycle. It focuses on key topics including wastewater collection, treatment
processes, safety, regulations, and operational practices. The guide contains over 100
practice questions, each with a clear answer and an in-depth explanation to build
understanding. Questions are drawn from reliable sources and verified for accuracy. Use
this to test knowledge, identify weak areas, and reinforce concepts essential for passing
the exam and excelling in the field.
Section 1: Wastewater Fundamentals and Regulations
(Questions 1-20)
1. Question: What is the primary objective of the Clean Water Act of 1972?
Answer: Restore and maintain the chemical, physical, and biological integrity of
water in the US.
, Explanation: The Clean Water Act sets goals to protect water bodies from pollution
by regulating discharges and ensuring safe water for fishing and swimming. In
Texas, this supports TCEQ permits that limit pollutants like BOD and TSS in effluent,
helping operators maintain compliance and prevent environmental harm from
untreated wastewater.
2. Question: What does NPDES stand for?
Answer: National Pollutant Discharge Elimination System.
Explanation: NPDES is the federal program under the EPA that controls point source
pollution into US waters. In Texas, TCEQ administers it for wastewater plants, requiring
operators to monitor and report discharges to avoid fines and ensure effluent meets limits,
such as no more than 30 mg/L BOD5.
3. Question: Chapter _____ of the Texas Water Code is the state law controlling water
pollution and _____ authority to control discharges in Texas.
Answer: Chapter 26; TCEQ.
Explanation: Chapter 26 empowers TCEQ to issue permits, set standards, and enforce
rules for wastewater treatment. Operators must follow these to operate legally, including
daily monitoring of flows and residuals, which prevents illegal discharges and protects
public health from pathogens.
4. Question: The name of the State Agency responsible for enforcing pollution control
laws in Texas is?
Answer: Texas Commission on Environmental Quality (TCEQ).
Explanation: TCEQ oversees licensing, inspections, and compliance for wastewater
systems. Class I operators report to TCEQ on plant performance, ensuring treatment
removes 85-95% of pollutants before discharge, which safeguards rivers and groundwater
from contamination.
5. Question: A licensed wastewater operator is a professional who?
Answer: Protects public health, operates treatment systems safely, and complies with
regulations.
, Explanation: Operators manage collection and treatment to remove solids, organics, and
pathogens. This role involves daily checks on pumps, clarifiers, and disinfection, reducing
disease risks like cholera and maintaining Texas stream standards for dissolved oxygen
above 5 mg/L.
6. Question: What is TCEQ doing to control "point source" pollution of the Texas
waterways?
Answer: Permitting of domestic and industrial wastewater plants.
Explanation: Point sources are direct discharges from pipes. TCEQ issues Texas Pollutant
Discharge Elimination System (TPDES) permits with limits on parameters like pH (6-9) and
chlorine residual (1 mg/L), allowing operators to adjust processes for consistent effluent
quality.
7. Question: The term pathogenic means?
Answer: Capable of causing disease.
Explanation: Pathogens in wastewater include bacteria and viruses that spread illness.
Treatment like chlorination kills 99.99% of them, with operators verifying via fecal coliform
tests (under 200/100mL), preventing outbreaks in communities relying on treated water
reuse.
8. Question: The minimum separation between sewer lines and potable water lines
is?
Answer: 9 feet.
Explanation: This vertical separation prevents cross-contamination from leaks. In Texas,
it's a TCEQ rule to avoid groundwater pollution; operators inspect lines regularly to ensure
no breaches, protecting drinking water supplies from sewage intrusion.
9. Question: An important step in testing a sample for Total Suspended Solids (TSS)
is?
Answer: Filtering the sample.
Explanation: TSS measures particles caught on a filter after drying at 103°C. It's key for
efficiency (aim for <30 mg/L effluent); high TSS indicates poor settling, prompting operators
to adjust sludge wasting for clearer discharge.
