TCEQ Wastewater Collection
System Operator Class I — Form A
Exam Questions and Correct
Answers with Detailed Rationales |
2026/2027 Edition | Exam Prep
Study Guide PDF
1. What is the primary purpose of a wastewater collection
system?
A. To treat wastewater before discharge
B. To collect and convey wastewater to a treatment facility
C. To disinfect drinking water
D. To generate electricity from sewage
Answer: B. To collect and convey wastewater to a treatment
facility
Rationale: A wastewater collection system is designed to receive
wastewater from homes, businesses, and other sources and
transport it safely to a wastewater treatment facility. Treatment,
disinfection, and final discharge are functions of the treatment
process rather than the collection system itself.
2. Which type of sewer system relies primarily on gravity to
move wastewater?
A. Force main system
B. Pressure sewer system
,C. Gravity sewer system
D. Vacuum sewer system
Answer: C. Gravity sewer system
Rationale: Gravity sewer systems are designed with sufficient
slope so wastewater flows downhill under the force of gravity.
Proper pipe slope and hydraulic design are essential to maintain
adequate flow velocities and prevent excessive solids deposition.
3. What is the main function of a manhole in a wastewater
collection system?
A. To disinfect wastewater
B. To provide access for inspection, maintenance, and cleaning
C. To increase wastewater pressure
D. To remove dissolved oxygen
Answer: B. To provide access for inspection, maintenance,
and cleaning
Rationale: Manholes provide operators with access to
underground sewer lines. They are commonly located at changes
in direction, changes in grade, pipe intersections, and other
locations where inspection, cleaning, or maintenance may be
required.
4. Which condition is most likely to cause excessive solids
deposition in a gravity sewer?
A. Excessive flow velocity
B. Adequate pipe slope
,C. Low flow velocity
D. Proper pipe alignment
Answer: C. Low flow velocity
Rationale: Wastewater must maintain enough velocity to
transport suspended solids through the sewer. When velocity
becomes too low, heavier materials can settle to the bottom of
the pipe, eventually contributing to blockages, odors, and
reduced hydraulic capacity.
5. What is infiltration in a wastewater collection system?
A. Wastewater entering a drinking-water system
B. Groundwater entering a sewer through defects or openings
C. Stormwater intentionally discharged into a treatment plant
D. Industrial wastewater entering a force main
Answer: B. Groundwater entering a sewer through defects or
openings
Rationale: Infiltration occurs when groundwater enters the
collection system through cracks, defective joints, deteriorated
manholes, or other openings below or near the groundwater table.
Excessive infiltration increases flow to the treatment plant and
can reduce available collection-system capacity.
6. What is inflow?
A. Groundwater entering through cracks below the water table
B. Direct entry of water into a sewer from sources such as roof
drains or storm connections
, C. Wastewater entering a treatment basin
D. Water leaking from a force main into the soil
Answer: B. Direct entry of water into a sewer from sources
such as roof drains or storm connections
Rationale: Inflow is water that enters a sanitary sewer through
direct connections or openings that allow relatively rapid entry of
rainfall or surface water. Examples can include improper roof-
drain connections, yard drains, storm drains, and damaged
manhole covers.
7. Which observation during manhole inspection could
indicate infiltration?
A. Dry interior walls during dry weather
B. Groundwater visibly entering through a joint
C. Properly seated manhole cover
D. Normal wastewater flow
Answer: B. Groundwater visibly entering through a joint
Rationale: Visible water entering through a pipe joint, crack, or
wall penetration during dry-weather conditions is a common
indication of infiltration. Operators should document the location
and severity so repairs can be prioritized.
8. What is the primary purpose of sewer pipe slope?
A. To prevent all wastewater flow
B. To provide the hydraulic gradient necessary for gravity flow
C. To increase pipe diameter
D. To eliminate the need for manholes
System Operator Class I — Form A
Exam Questions and Correct
Answers with Detailed Rationales |
2026/2027 Edition | Exam Prep
Study Guide PDF
1. What is the primary purpose of a wastewater collection
system?
A. To treat wastewater before discharge
B. To collect and convey wastewater to a treatment facility
C. To disinfect drinking water
D. To generate electricity from sewage
Answer: B. To collect and convey wastewater to a treatment
facility
Rationale: A wastewater collection system is designed to receive
wastewater from homes, businesses, and other sources and
transport it safely to a wastewater treatment facility. Treatment,
disinfection, and final discharge are functions of the treatment
process rather than the collection system itself.
2. Which type of sewer system relies primarily on gravity to
move wastewater?
A. Force main system
B. Pressure sewer system
,C. Gravity sewer system
D. Vacuum sewer system
Answer: C. Gravity sewer system
Rationale: Gravity sewer systems are designed with sufficient
slope so wastewater flows downhill under the force of gravity.
Proper pipe slope and hydraulic design are essential to maintain
adequate flow velocities and prevent excessive solids deposition.
3. What is the main function of a manhole in a wastewater
collection system?
A. To disinfect wastewater
B. To provide access for inspection, maintenance, and cleaning
C. To increase wastewater pressure
D. To remove dissolved oxygen
Answer: B. To provide access for inspection, maintenance,
and cleaning
Rationale: Manholes provide operators with access to
underground sewer lines. They are commonly located at changes
in direction, changes in grade, pipe intersections, and other
locations where inspection, cleaning, or maintenance may be
required.
4. Which condition is most likely to cause excessive solids
deposition in a gravity sewer?
A. Excessive flow velocity
B. Adequate pipe slope
,C. Low flow velocity
D. Proper pipe alignment
Answer: C. Low flow velocity
Rationale: Wastewater must maintain enough velocity to
transport suspended solids through the sewer. When velocity
becomes too low, heavier materials can settle to the bottom of
the pipe, eventually contributing to blockages, odors, and
reduced hydraulic capacity.
5. What is infiltration in a wastewater collection system?
A. Wastewater entering a drinking-water system
B. Groundwater entering a sewer through defects or openings
C. Stormwater intentionally discharged into a treatment plant
D. Industrial wastewater entering a force main
Answer: B. Groundwater entering a sewer through defects or
openings
Rationale: Infiltration occurs when groundwater enters the
collection system through cracks, defective joints, deteriorated
manholes, or other openings below or near the groundwater table.
Excessive infiltration increases flow to the treatment plant and
can reduce available collection-system capacity.
6. What is inflow?
A. Groundwater entering through cracks below the water table
B. Direct entry of water into a sewer from sources such as roof
drains or storm connections
, C. Wastewater entering a treatment basin
D. Water leaking from a force main into the soil
Answer: B. Direct entry of water into a sewer from sources
such as roof drains or storm connections
Rationale: Inflow is water that enters a sanitary sewer through
direct connections or openings that allow relatively rapid entry of
rainfall or surface water. Examples can include improper roof-
drain connections, yard drains, storm drains, and damaged
manhole covers.
7. Which observation during manhole inspection could
indicate infiltration?
A. Dry interior walls during dry weather
B. Groundwater visibly entering through a joint
C. Properly seated manhole cover
D. Normal wastewater flow
Answer: B. Groundwater visibly entering through a joint
Rationale: Visible water entering through a pipe joint, crack, or
wall penetration during dry-weather conditions is a common
indication of infiltration. Operators should document the location
and severity so repairs can be prioritized.
8. What is the primary purpose of sewer pipe slope?
A. To prevent all wastewater flow
B. To provide the hydraulic gradient necessary for gravity flow
C. To increase pipe diameter
D. To eliminate the need for manholes
