TCEQ WASTEWATER CLASS D LICENSE PREP EXAM QUESTIONS AND
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026
Q&A | INSTANT DOWNLOAD PDF
CORE DOMAINS
Wastewater Regulations and Compliance
Wastewater Characteristics and Preliminary Treatment
Collection Systems and Lift Stations
Primary and Secondary Treatment Processes
Disinfection and Laboratory Testing
Safety and Confined Space Operations
Pumps, Motors, and Equipment Maintenance
Basic Math and Flow Calculations
INTRODUCTION
The TCEQ Wastewater Class D License Preparation Examination
assesses the competency of entry-level candidates seeking certification
as wastewater treatment facility operators in Texas. This
comprehensive assessment evaluates knowledge across critical domains
including wastewater regulations, treatment processes, collection
systems, safety procedures, and basic operations. The examination
employs multiple-choice and scenario-based questions that require
candidates to demonstrate applied decision-making skills essential for
real-world wastewater operations. Emphasis is placed on TCEQ
regulatory requirements, safety standards, and practical operational
knowledge. Successful completion validates the candidate's readiness to
,operate Class D wastewater facilities in compliance with Texas
regulations.
SECTION ONE: QUESTIONS 1–100
Question 1
A Class D wastewater operator license in Texas authorizes the operator
to manage which of the following systems independently?
A. Activated sludge plants serving populations up to 10,000
B. Total retention lagoons and collection systems serving a population
of 1,500 or less
C. Any wastewater facility with flow under 1 MGD
D. Collection systems only
B. Total retention lagoons and collection systems serving a
population of 1,500 or less
RATIONALE: A Class D wastewater operator license is specifically
authorized for operators of total retention lagoon systems or collection
systems serving a population of 1,500 or less. Larger activated sludge
plants require a Class C license or higher.
Question 2
What is the minimum education requirement for a TCEQ Class D
Wastewater Operator license?
A. High school diploma or GED
B. Associate degree in environmental science
,C. No formal education requirement
D. Bachelor's degree in engineering
C. No formal education requirement
RATIONALE: According to TCEQ licensing requirements, a Class D
Wastewater license requires no formal education. The only training
requirement is completion of the Basic Wastewater Operation course.
Question 3
What is the application fee for a TCEQ Class D Wastewater Operator
license?
A. $50
B. $74
C. $111
D. $150
B. $74
RATIONALE: The application fee for a Class D Wastewater license is
$74. A Class C license requires a $111 fee.
Question 4
A provisional Wastewater Class D license is issued to applicants who do
not currently have which of the following?
A. Work experience
B. High school diploma or GED
C. Training course completion
D. Examination passage
, B. High school diploma or GED
RATIONALE: A provisional Class D is issued to applicants who do not
currently have a high school diploma or GED. It is valid for 2 years and
must be upgraded to the full Class D or higher license at the end of the
validity period.
Question 5
Under 30 TAC Chapter 217, what is the required minimum physical
separation at potable water connections to wastewater systems?
A. A reduced pressure zone backflow assembly
B. A 2-inch physical air gap
C. A double-check valve assembly
D. A swing check valve
B. A 2-inch physical air gap
RATIONALE: 30 TAC Chapter 217 requires a minimum 2-inch
physical air gap at all potable water supply connections to prevent
cross-contamination. Physical breaks are prioritized over mechanical
valves for cross-connection control.
Question 6
What is the minimum velocity required in a gravity sewer to keep solids
in suspension?
A. 1 ft/sec
B. 2 ft/sec
C. 3 ft/sec
D. 5 ft/sec
CORRECT ANSWERS (VERIFIED ANSWERS) PLUS RATIONALES 2026
Q&A | INSTANT DOWNLOAD PDF
CORE DOMAINS
Wastewater Regulations and Compliance
Wastewater Characteristics and Preliminary Treatment
Collection Systems and Lift Stations
Primary and Secondary Treatment Processes
Disinfection and Laboratory Testing
Safety and Confined Space Operations
Pumps, Motors, and Equipment Maintenance
Basic Math and Flow Calculations
INTRODUCTION
The TCEQ Wastewater Class D License Preparation Examination
assesses the competency of entry-level candidates seeking certification
as wastewater treatment facility operators in Texas. This
comprehensive assessment evaluates knowledge across critical domains
including wastewater regulations, treatment processes, collection
systems, safety procedures, and basic operations. The examination
employs multiple-choice and scenario-based questions that require
candidates to demonstrate applied decision-making skills essential for
real-world wastewater operations. Emphasis is placed on TCEQ
regulatory requirements, safety standards, and practical operational
knowledge. Successful completion validates the candidate's readiness to
,operate Class D wastewater facilities in compliance with Texas
regulations.
SECTION ONE: QUESTIONS 1–100
Question 1
A Class D wastewater operator license in Texas authorizes the operator
to manage which of the following systems independently?
A. Activated sludge plants serving populations up to 10,000
B. Total retention lagoons and collection systems serving a population
of 1,500 or less
C. Any wastewater facility with flow under 1 MGD
D. Collection systems only
B. Total retention lagoons and collection systems serving a
population of 1,500 or less
RATIONALE: A Class D wastewater operator license is specifically
authorized for operators of total retention lagoon systems or collection
systems serving a population of 1,500 or less. Larger activated sludge
plants require a Class C license or higher.
Question 2
What is the minimum education requirement for a TCEQ Class D
Wastewater Operator license?
A. High school diploma or GED
B. Associate degree in environmental science
,C. No formal education requirement
D. Bachelor's degree in engineering
C. No formal education requirement
RATIONALE: According to TCEQ licensing requirements, a Class D
Wastewater license requires no formal education. The only training
requirement is completion of the Basic Wastewater Operation course.
Question 3
What is the application fee for a TCEQ Class D Wastewater Operator
license?
A. $50
B. $74
C. $111
D. $150
B. $74
RATIONALE: The application fee for a Class D Wastewater license is
$74. A Class C license requires a $111 fee.
Question 4
A provisional Wastewater Class D license is issued to applicants who do
not currently have which of the following?
A. Work experience
B. High school diploma or GED
C. Training course completion
D. Examination passage
, B. High school diploma or GED
RATIONALE: A provisional Class D is issued to applicants who do not
currently have a high school diploma or GED. It is valid for 2 years and
must be upgraded to the full Class D or higher license at the end of the
validity period.
Question 5
Under 30 TAC Chapter 217, what is the required minimum physical
separation at potable water connections to wastewater systems?
A. A reduced pressure zone backflow assembly
B. A 2-inch physical air gap
C. A double-check valve assembly
D. A swing check valve
B. A 2-inch physical air gap
RATIONALE: 30 TAC Chapter 217 requires a minimum 2-inch
physical air gap at all potable water supply connections to prevent
cross-contamination. Physical breaks are prioritized over mechanical
valves for cross-connection control.
Question 6
What is the minimum velocity required in a gravity sewer to keep solids
in suspension?
A. 1 ft/sec
B. 2 ft/sec
C. 3 ft/sec
D. 5 ft/sec
