TCEQ Wastewater Collection
System Operator Class I 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 drinking water
B. To store potable water
C. To collect and convey wastewater to a treatment facility
D. To disinfect stormwater
Answer: C. To collect and convey wastewater to a treatment
facility
Rationale: A wastewater collection system is designed to receive
wastewater from residences, businesses, and other sources and
convey it safely to a wastewater treatment facility. The collection
system itself generally transports wastewater rather than
providing the complete treatment process.
2. Under current TCEQ requirements, a Category I wastewater
collection system generally has a daily average flow of:
,A. Less than 10,000 gallons per day
B. Less than 100,000 gallons per day
C. 100,000 to 1 million gallons per day
D. Greater than 1 million gallons per day
Answer: B. Less than 100,000 gallons per day
Rationale: TCEQ classifies wastewater collection systems
according to daily average flow. Category I systems have a daily
average flow of less than 100,000 gallons per day. Category II
systems range from 100,000 gallons per day to 1 million gallons
per day, while Category III systems have flows greater than 1
million gallons per day.
3. What is the minimum license class required for a Category I
wastewater collection system under the TCEQ classification?
A. Collection Class I or Wastewater Class D
B. Collection Class II or Wastewater Class C
C. Collection Class III or Wastewater Class B
D. Wastewater Class A only
Answer: A. Collection Class I or Wastewater Class D
Rationale: TCEQ's current collection-system requirements specify
that a Category I system, with a daily average flow of less than
100,000 gallons per day, requires at least a Collections Class I or
Wastewater Class D license.
4. Which of the following is a typical source of domestic
wastewater?
,A. Raw petroleum only
B. Household sanitary sewage
C. Treated drinking water only
D. Atmospheric moisture
Answer: B. Household sanitary sewage
Rationale: Domestic wastewater primarily originates from
residences and similar facilities. It can contain human waste,
wash water, food residues, soaps, detergents, and other materials
discharged through plumbing fixtures.
5. What is infiltration in a wastewater collection system?
A. Wastewater leaking from a sewer into the soil
B. Groundwater entering a sewer through defects or joints
C. Chemicals being injected into a sewer
D. Air entering a force main during pumping
Answer: B. Groundwater entering a sewer through defects or
joints
Rationale: Infiltration is groundwater that enters a collection
system through defects such as cracked pipes, defective joints,
deteriorated manholes, or improperly sealed connections.
Infiltration can increase wastewater flows and hydraulic loading
on downstream facilities.
6. What is inflow?
A. Groundwater entering through defective pipe joints below the
water table
B. Stormwater entering the collection system through direct
, connections or openings
C. Wastewater entering a treatment plant
D. Air entering a gravity sewer
Answer: B. Stormwater entering the collection system through
direct connections or openings
Rationale: Inflow is water that enters a sanitary sewer from
sources such as roof drains, yard drains, storm drains, manhole
covers, or other direct connections. Unlike infiltration, inflow is
generally associated with rainfall or surface-water conditions and
direct pathways into the system.
7. Which condition is most likely to cause excessive
infiltration?
A. A properly sealed new pipe
B. A cracked sewer pipe located below the groundwater table
C. A watertight force main
D. A properly constructed service connection
Answer: B. A cracked sewer pipe located below the
groundwater table
Rationale: A crack below the groundwater table can provide a
pathway for groundwater to enter the sewer. The quantity of
infiltration may increase substantially during periods when
groundwater levels are elevated.
8. What is the primary function of a manhole in a gravity sewer
system?
System Operator Class I 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 drinking water
B. To store potable water
C. To collect and convey wastewater to a treatment facility
D. To disinfect stormwater
Answer: C. To collect and convey wastewater to a treatment
facility
Rationale: A wastewater collection system is designed to receive
wastewater from residences, businesses, and other sources and
convey it safely to a wastewater treatment facility. The collection
system itself generally transports wastewater rather than
providing the complete treatment process.
2. Under current TCEQ requirements, a Category I wastewater
collection system generally has a daily average flow of:
,A. Less than 10,000 gallons per day
B. Less than 100,000 gallons per day
C. 100,000 to 1 million gallons per day
D. Greater than 1 million gallons per day
Answer: B. Less than 100,000 gallons per day
Rationale: TCEQ classifies wastewater collection systems
according to daily average flow. Category I systems have a daily
average flow of less than 100,000 gallons per day. Category II
systems range from 100,000 gallons per day to 1 million gallons
per day, while Category III systems have flows greater than 1
million gallons per day.
3. What is the minimum license class required for a Category I
wastewater collection system under the TCEQ classification?
A. Collection Class I or Wastewater Class D
B. Collection Class II or Wastewater Class C
C. Collection Class III or Wastewater Class B
D. Wastewater Class A only
Answer: A. Collection Class I or Wastewater Class D
Rationale: TCEQ's current collection-system requirements specify
that a Category I system, with a daily average flow of less than
100,000 gallons per day, requires at least a Collections Class I or
Wastewater Class D license.
4. Which of the following is a typical source of domestic
wastewater?
,A. Raw petroleum only
B. Household sanitary sewage
C. Treated drinking water only
D. Atmospheric moisture
Answer: B. Household sanitary sewage
Rationale: Domestic wastewater primarily originates from
residences and similar facilities. It can contain human waste,
wash water, food residues, soaps, detergents, and other materials
discharged through plumbing fixtures.
5. What is infiltration in a wastewater collection system?
A. Wastewater leaking from a sewer into the soil
B. Groundwater entering a sewer through defects or joints
C. Chemicals being injected into a sewer
D. Air entering a force main during pumping
Answer: B. Groundwater entering a sewer through defects or
joints
Rationale: Infiltration is groundwater that enters a collection
system through defects such as cracked pipes, defective joints,
deteriorated manholes, or improperly sealed connections.
Infiltration can increase wastewater flows and hydraulic loading
on downstream facilities.
6. What is inflow?
A. Groundwater entering through defective pipe joints below the
water table
B. Stormwater entering the collection system through direct
, connections or openings
C. Wastewater entering a treatment plant
D. Air entering a gravity sewer
Answer: B. Stormwater entering the collection system through
direct connections or openings
Rationale: Inflow is water that enters a sanitary sewer from
sources such as roof drains, yard drains, storm drains, manhole
covers, or other direct connections. Unlike infiltration, inflow is
generally associated with rainfall or surface-water conditions and
direct pathways into the system.
7. Which condition is most likely to cause excessive
infiltration?
A. A properly sealed new pipe
B. A cracked sewer pipe located below the groundwater table
C. A watertight force main
D. A properly constructed service connection
Answer: B. A cracked sewer pipe located below the
groundwater table
Rationale: A crack below the groundwater table can provide a
pathway for groundwater to enter the sewer. The quantity of
infiltration may increase substantially during periods when
groundwater levels are elevated.
8. What is the primary function of a manhole in a gravity sewer
system?
